Development of an Automated Airfield Dynamic Cone Penetrometer (AADCP) prototype and the evaluation of unsurfaced airfie...

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Title:
Development of an Automated Airfield Dynamic Cone Penetrometer (AADCP) prototype and the evaluation of unsurfaced airfield seismic surveying using Spectral Analysis of Surface Waves (SASW) technology
Physical Description:
xix, 290 leaves : ill. ; 29 cm.
Language:
English
Creator:
Weintraub, David
Publication Date:

Subjects

Genre:
bibliography   ( marcgt )
theses   ( marcgt )
non-fiction   ( marcgt )

Notes

Thesis:
Thesis (Ph. D.)--University of Florida, 1993.
Bibliography:
Includes bibliographical references (leaves 282-287).
Statement of Responsibility:
by David Weintraub.
General Note:
Typescript.
General Note:
Vita.

Record Information

Source Institution:
University of Florida
Rights Management:
All applicable rights reserved by the source institution and holding location.
Resource Identifier:
aleph - 001950914
notis - AKC7456
oclc - 31200859
System ID:
AA00003265:00001

Full Text












DEVELOPMENT OF AN AUTOMATED AIRFIELD DYNAMIC CONE PENETROMETER
(AADCP) PROTOTYPE AND THE EVALUATION OF UNSURFACED AIRFIELD
SEISMIC SURVEYING USING SPECTRAL ANALYSIS OF SURFACE WAVES (SASW)
TECHNOLOGY














By


DAVID


WEINTRAUB






























Copyright


David


1993


Weintraub




























This


dissertation


dedicated


Lord


and


Savior


Jesus


Christ,


my loving


wife


, Ellen,


daughter,


Layna


Jenee.


also


dedicated


father


, Edward


Weintraub


, who


passed


away


during


this


work


but


was


extremely


excited


to have


son


in the


U.S.


Air


Force


and


studying


his


doctorate


degree.
















ACKNOWLEDGEMENTS


There


are


several


individuals


to whom


owe


tremendous


amount


of appreciation


developing


and


preparing


this


ssertation.


It is


not


often


that


a person


can


be surrounded


so many


skillful


professionals


technicians


one


place.


Wisdom


, knowledge,


understanding


only


come


from


one


source


, God


the


Father.


The


bible


says


that


Jesus,


His


son,


the


way,


the


truth


life


and


that


no one


comes


the


Father


except


through


Him.


The


bible


says


that


anyone


lacks


wisdom,


he should


simply


ask


and


will


given


unto


him.


thank


God


that


when


I did


ask


that


was


faithful


to supply


me direction


times


every


need.


when


He inspired


"ideas"


ran


me and


out.


gave


simply


acknowledge


that


creativity


, wisdom,


and


understanding


received


this


dissertation


was


from


God


who


worked


through


many


people


mentioned


below.


Dr John


Davidson


served


as my


committee


chairman,


coach,


and


friend.


was


invaluable


to this


research


effort


with


words


of encouragement,


direction


, and


focus.


.









Dr David


advisor.


Bloomquist


ability


served


to analyze


as my


"ultimate


a problem


and


technical


reach


practical


conclusion


was


phenomenal.


gratitude


extended


him


his


countless


hours


of brainstorming


with


me and


Dr Mike


teaching


McVay


served


me to be quick


as my


on my


theoretical


feet.


advisor


been


a tremendous


teach


impression


to think


apply


on my


logically,


asset


to the


theoretical


career.


stand


research.


concepts


want


on my


has


to thank


own


His


made


him


to defend


ability


a lasting


forcing


a subject


matter,


listen


carefully


to what


others


have


say.


Dr Brisbane


committee.


Brown


I personal


served

y thank


as the


outside


Dr Brown


member

sharing


on my

his


innovative


ideas


and


taking


time


to discuss


them


with


me.


COE


experience


provided


a practical


insight


into


project


that


otherwi


would


have


been


missed.


Captain


Mike


Coats


and


Captain


Chris


Foreman


served


Air


Force


project


coordinators


and


did


an outstanding


job.


appreciate


their


professional


support


and


interest


the


project


that


allowed


me to call


them


any


time


deal


with


a problem.


Not


many


people


have


that


kind


support.


was


fortunate


to have


served


with


them


on this


dissertation


project.


Dr Ralph


"Rugby"


Ellis


served


as my


construction









Thumper,


" and


been


instrumental


shaping


prof


ess


ional


development


here


University


of Florida.


Dr Paul

Department c


Thompson


chairman


served


while


as the

attended


Civil

the


Engineering


University


Florida.


want


thank


him


the


time


he spent


with


on career


development


as a civil


engineer


and


an officer


the


U.S


. Air


Force.


Ed Dobson


served


as my


technical


advisor


extraordinaire.


I want


thank


Ed for


patience


while


spending


field


time


testing,


with


and


me teaching


tool


basics


maintenance.


of shop


He has


mechani


instilled


the


fact


that


everything


place


the


shop.


Bill


Studstill


and


"Boyz"


(Hubert,


Josh,


Tom


, and


Karl)


played


a major


supportive


role


the


completion


project


appreciate


their


time


and


energy


helping


buy,


install,


tear


apart


literally


hundreds


of odd


parts


and


pieces.


It i


a bles


sing


see


what


happens


when


people


are


unity.


The


Machine


Shop


(Dale,


Karl,


Hermann,


Tommy,


Charlie,


and


Bill)


were


great


friends


throughout


the


manufacturing


process


and


the


machine


project.


intricate


With


parts,


Dale


the


and


project


ability


seemed


to weld


run


smoothly


appreciate


efforts.


Mr Pedro


Ruesta,


fellow


PhD


student,


became


a great









hours


feedback


and


encouragement


throughout


the


project.


His


geotechnical


computer


skills


were


a tremendous


benefit


to the


project.














TABLE


OF CONTENTS


Page


ACKNOWLEDGEMENTS......................................


LIST

LIST


OF TABLES.... .. .......... ..... ..... ..... ...

OF FIGURES. ....... ...... .. .......... .


xiii
X1iv
xiv


XViii


ABSTRACT........................................... .

CHAPTERS


1 INTRODUCTION


Problem Statement
Objectives......
Overview........


....... ...... . 1


.........*....*.*....S .....
.... ...............*.*.*......
...............*... .......*5S
. .. . .
. .


REVIEW


OF THE


LITERATURE............................


Introduction.......
Unsurfaced Airfield


Trafficability


.........
.........


Introduction.
Measurement o
ng Capacity of
Introduction.
Airfield Cone
Dynamic Cone
.3.3.1 Introd
.3.3.2 DCP De


f


*...................
Soil Trafficability
Unsurfaced Airfields


.......Penetrometer
Penetrometer
Penetrometer
uction.......
scription....


(ACP)
(DCP).

.....


2.3.3.5


Correlation of CBR and DCP..
Dynamic Cone Penetrometer
Mathematical Models ........
Force Analysis of the Dynami
Cone Penetrometer..........


Stress


Aerial
SSurvey
Introdu
Surface


Wave


Other Dynamic
Penetrometers
Penetrometers
ing..........
ction........


Wa
'. .


Propagation.


Cone


......
* .


ve Propagation..


.* .. ..


Ia











Determining
and Modulus


Surface Layer Thickness
Values...................


DEVELOPMENT
DYNAMIC CONE


AND DESCRIPTION OF THE
PENETROMETER (AADCP)


AUTOMATED
EQUIPMENT.


AIRFIELD
.. .. e..


Introduction...........
Selection of Testing Sys
3.2.1 Introduction.....
3.2.2 System Specificat
3.2.3 Review of Current
Prototype Development...
3.3.1 Rod and Guide Mou


Air Piston.....
Rotary Hammer..
Cam Operated Li
Mechanism......
Chain Driven Li
Mechanism.....
Air Piston-Spri
Mechanism......


tem.


ions.....
Technology

nted to an


and


. . .



...... .


.....

Drop


fting-Drop

na Lift and


. *


Modifications of the
Design......... ..
.3.6.1 Introduction.


Drop


.0...0
AADCP
S S *S S


Air Exhaustion................
Spring Reaction Force.........
Penetrometer Rod Modifications


3.4 Description
Dynamic Cone
3.4.1 Intro
3.4.2 Penet
3.4.3 Contr
3.4.4 Power

DESCRIPTION OF THE
WAVE EQUIPMENT.....


the


Automated


Penetrometer


duction.......
ration System.
ol System.....
System.......


SPECTRAL


Introduction....
Digital Analyzer
Signal Receivers


S. .

. .
S. .
and


Airfield


* S S S S O S

a S S S S S S
. ..... . ...
..................
..................
..................
..................


ANALYSIS





Impact S


OF SURFACE


ource.


source.


.........

...0.....
........
.....0...
* S S S S

* S S SS
S S S S S


FIELD TESTING AND CORRELATION OF THE AUTOMATED
AIRFIELD DYNAMIC CONE PENETROMETER (DCP) WITH THE
DYNAMIC CONE PENETROMETER (AADCP)..............


Introduction..........


... ............
...............











Discuss
DCP vs A
Test Obj
Correlat
Correlat
Discuss
Test Res


on of
ADCP


Results......
Testing.......


ectives
ion Tes
ion Tes
on of C
ults...


t Procedures
t Results...
orrelation


....OO....

.......O..
.........
.........
* S* *.
* S S S *
* *. S SS *
* S
* S S .


EVALUATION OF SEISMIC
SASW TECHNIQUES.......


SURVEYING


FIELD


TESTING


USING


Introduction..


SASW
SASW
SASW
SASW
Disc
6.6.
6.6.


Test O
Test S
Test P
Test R
ssion
Kana
FDOT


object
ites.
roced
result
of SA
paha
Test


ives.
....
ures.

SW Re
Site.
Pit


000000.0.0.0...000000..
...."...... .... ... ..*. .
. . .* . ...


suit

#1..


* . . S O S . .
............. .. ...
...................


CONCLUSIONS


AND


Conclusions
Recommendat
7.2.1 Airf
7.2.2 Airf
7.2.3 Modi


ions for Future
field Evaluation
field Evaluation
fications to the


Testing.....
Using SASW..
Using Roboti
AADCP......


....e


APPENDICES


DCP


RELIABILITY


TESTING


DATA.............. ... .


A.1

A.2


A.5

A.6


Archer
Estimat
Archer
Calcula
Archer
Archer
Penetra
Maguire
CBR Est
Maguire


Landf
ions.
Landf
tions
Landf
Landf
tion.
Hous
imati
Hous


Calculation
A.7 Maguire Hou
A.8 Maguire Hou
Penetration
A.9 Lake Alice


DCP


Manual

Average


Estimated
Manual DCP


"....
Area
'....
Area

Area
Area


s
s
S
s
.


Pkg Lot


Raw


Data


Estimated


and


..CBR..
CBR


CBR Profile
Blows vs


CBR


.....O

......
......
* *S

* .. .*
* .. ..


Manual DCP Raw Data


Average Estimated


Estimated
Manual DCP


Manual


DCP


and


'....
CBR


CBR Profile.
Blows vs


Raw


Data


and


RECOMMENDATIONS....................










A.12 Lake Alice Pkg L
Penetration.....
A.13 Lake Alice Shore
CBR Estimations.
A.14 Lake Alice Shore
Calculations....
A.15 Lake Alice Shore
A.16 Lake Alice Shore
Penetration.....
A.17 SW 24 Ave Quarry
Estimations.....
A.18 SW 24 Ave Quarry
Calculations....
A.19 SW 24 Ave Quarry
A.20 SW 24 Ave Quarry


ot


line

line

line
line


Manual


DCP


Manua...
Manual


Blows


DCP Raw Data


Average Estimated


Estimated
Manual DCP
S .. .


Manual


DCP


Raw


S...
and


a....
CBR


CBR Profile.
Blows vs


Data


and


Average Estimated CBR.
Average Estimated CBR


..a .......
Estimated
Manual DCP


a...a...0*..
CBR Profile.
Blows vs


CBR


A.21

A.22

A.23
A.24


Penetrat
Newberry
Estimati
Newberry
Calculat
Newberry
Newberry


ion..
Farm
ons..
Farm
ions.
Farm
Farm


....Manual..
Manual


DCP


Raw


Data


Average Estimated


Estimated
Manual DCP


and


. .
CBR


CBR Profil
Blows vs


CBR


........


........
* .. .. ..
* *. .


Penetration..


KANAPAHA


SASW


TESTING


SITE


B.1 Kanapah
B.2 Kanapah
CBR Est
B.3 Kanapah
Calcula
B.4 Kanapah
B.5 Kanapah
Penetra
B.6 Kanapah
CBR Est
B.7 Kanapah
Calcula
B.8 Kanapah
B.9 Kanapah
Penetra
B.10 Kanapah
CBR Est
B.11 Kanapah
Calcula
B.12 Kanapah
B.13 Kanapah


Site


tes
ions
tes
s...
tes
tes


tion.....
a Sites 7
imations.
a Sites 7
tions....
a Sites 7
a Sites 7
tion.....
a Sites 1
imations.
a Sites 1
tions....
a Sites 1
a Sites 1


Locations..


-6 Manual


DCP


Raw


Data


Average Estimated


Estimated
Manual DCP


.....Manual
Manual


and


* ..
CBR


CBR Profil
Blows vs


a. .. a... ata
DCP Raw Data


Average Estimated


Estimated
Manual DCP
.........6 Manual DC
6 Manual DC


Average Es
a..........
Estimated
Manual DCP


a....
and


CBR


CBR Profil
Blows vs

P Raw Data


timated


a
and


*
CBR


CBR Profile..
Blows vs


.............


DATA................










Archer
Archer
Archer
Archer


Land
Land
Land
Land


Spreadsheet 2
AADCP and DCP
DCP vs Depth.


CBR


vs Depth.


* *
Blow


Profile.


*
...........
...........


Magu
Magu
Magu
Magu
Magu
Lake
Lake
Lake
Prof
Lake
Lake
Lake
Lake
Lake
Prof
Lake
Lake
FDOT
FDOT
FDOT
Prof
FDOT
FDOT


Spreadsheet 1
Spreadsheet 2
AADCP and DCP
DCP vs Depth.
CBR vs Depth.


ice
ice
ice

ice
ice
ice
ice
ice
ice

ice
ice


Test
Test
Test
le..
Test
Test


Parking
Parking
Parking
Par.......
Parking
Parking
Shore L
Shore L
Shore L

Shore L
Shore L


Pit
Pit
Pit
Pit
Pit
Pit


S
S


Lot
Lot
Lot
* .
Lot
Lot
ine
ine
ine


Blow Profile


Spreadsheet 1
Spreadsheet 2
AADCP and DCP


DCP vs Depth
CBR vs Depth
Spreadsheet 1
Spreadsheet 2
AADCP and DCP


ine DCP vs
ine CBR vs
preadsheet
preadsheet


AADCP


and


Dept..
Depth
Depth


DCP


Se .
DCP vs Depth.
CBR vs Depth.


....

Blow


.....


Blow


Blow


......0..
.........
.........
* .
* .


....0.0.0
.....000.


FORCE AND ENERGY
INSTRUMENTS.....


MEASUREMENT


OF THE


AADCP


AND


DCP


Force and Ener
and Procedures
Force and Ener
Discussion of
Results.......


*gy
I..
'gy
Fo:


Measurement T

Measurement R
rce and Energy
S .... ....


est


Equipment


esults........
Measurement
... ... e.....


INSTRUCTIONAL


MANUAL


FOR


AADCP


TESTING.............


AADCP General Description
Penetration System.......
Control System...........
Power System............
AADCP Test Procedures....


REFERENCE LIST........................................


I










LIST


OF TABLES


TABLE


Page


ass


ification


Continuous


Dynamic


Penetrometers


International


Comparison


the


Equation
. .. .. .. 27


Log


CBR


Common


- B(Log


CBR-DCP


DCP) A


Relationships


....... 29


Variance


Coeffi


cient


Values


CBR


and


Tests


....... 37


Potential
Strokes..


Energy


Calculations


of Various


.. .. 100


Manual


DCP


Raw


Data


and


CBR


Estimations


(Archer


Landfill)


.. .. .. 138


Average


Estimated


CBR


Calculations


.... .. 143


Summary


Reliability


Summary o
DCP Relia

CV Values


Summary


the


Stadard


Testing


the


ability


Deviations


at Six


Coefficient


Testing

Testing


Inversion


Sites.


..... 145


of Variability


at Six

Sites.


Output


Sites

I....


of Site


....... 176


AADCP

AADCP


Field

Sample


Testing

Data C


Form....


orrelation


Worksheet.


. .... 23


-= A











LIST


OF FIGURES


Figure


Page


Unsurfaced


Airfield


Evaluation


Process.....


.. . 2


Cone


Index


vs Moisture


Content...


S.... 11


Design


Curve


the


Single


Wheel


Carrying


Capacity


of Unsurfaced


Runways.


... 14


Design


Curve


of Unsurfaced


the


Dual


Carrying


Capa


Runways.......


city
.... 14


Comparison
Capacity o


of Design
Unsurced


Curves
Runways


for
for


the
the


Carrying
C-130E.


Airfield


CBR


Cone


vs Airfield


Dynamic


Cone


enetrometer

Index.....

netrometer.


......O... .............

00........0...0.....0..


Blows


vs Penetration.....


. .. . . 25


Log


Plot


of CBR-DCP


Relationship


Assumed


Failure


Plane


Below


CBR


Plunger


. . .. 32


Effect


Mold


on CBR.


Field


CBR


Equipment


Assembled.


Comparison


Clay


of Predicted


Using


Cavity


and


Measured


Expansion


Cone


Index


Theory...


Comparison
for Mixed


Predicted


Using


Cavity


and


Measured


Expansion


Cone


Index


Theory..


.15 Comparison


Yuma


Predicted


Sand


Using


Cavity


Measured
Expansion


Cone


Index


Theory


Failure


Surface


Observed


with


Wedge


Penetration.


47


S............... 30


................... 33


S.................. 35










Acceleration,


Histories


Course


Velocity,


of DCP


Medium


S


Displacement
tiff Granular


Material.


Time
Base


S.... 51


Calculated


Force-Time


History


the


DCP


Granular


Base


Course


Material


...... .. .. 52


Aerial


Penetrometer..............


. .......... 57


.22 Approximated


Motion


with


Distribution


Depth


of Two


of Vertical
Wavelengths.


Parti


............ 62


Configuration


of SASW


Equipment.


.24 Phase


and


Coherence


Spectra.


.25 Composite


Dispersion


Curve..


.. .................. 70


Final


Shear


Wave


Velocity


Profil


. .... .. .. .... 71


.27 Qualitative


and


Empirical


Estimation


Shear


Wave


of Densities


Using


Velocities


Insitu


Dispersion


a Uniform


Curve


Rayle


Waves


Half-space.


Propagating


Dispersion
in a Softer


Dispers


a Stiffer


Curve


Layer


Curve


Layer


Rayleigh


Over


Waves


a Stiffer


Rayleigh


Over


Propagating


Half-space.


Waves


a Softer


Propagating


Half-space.


Determination


Surface


Layer


Thickness


from


the


Dispersion


Curve


Rayleigh


Wave


S.....


S... 78


Dispersion


Thickness


Curve


and


used


Young


to Determine


s Modulu


S..


Top
S..


Layer


Dispersion


Thickness


Curve


and


used


Young


Determine


Top


s Modulus


Layer
a a aa..@ ...


Rod


and


Guide


Mounted


an Air


ston.


Rotary


Hammer


Cam


Operated


Lift


Drop


Mechanism.


-a.rlr S .


rrI


.I I


__


r I










Automated


Air


Piston-Spring


Lift


Drop


Mechanism......


One-Way


.. 98


.. 104


Gripper


Modified


Solid


Penetration


Rod


with


Decoupling


of Instrument


and


Penetration


Rod..


General


Cone


View


the


Automated


Airfield


Penetrometer..


Dynamic


. .. 109


General


Air


Flow


Cylinder,


of AADCP

Piston


Operation..


Compression


Spring.


Quick


Exhaust


Valve.


..... 114


Source-Receiver


Configuration


of SASW


Equipment.


HP 35665

Complex


Dual

Signal


Channel


Time


Dynamic


and


Signal


Frequency


Analyzer

Domain..


Phase


the


Coherence


Cross


Power


Spectrum


and


Function..............


the


. . 124


Receiver


Spacing


Arrangements


SASW


Testing


126


Manual


DCP


used


as Impact


Source


SASW


Testing


Geographic


Locations


of Field


Testing


es.


UF Campus


Testing


Sites.


Off


Campus


Testing


Sites


Soil


Classification


Site


Summary.


. . .S . 133


Reliability


Test


Configuration.


. . . 136


Manual
Archer


Estimated
Archer La


DCP


Blows


vs Penetration


Landfill..


CBR


S. . . 141


Profile


ndfill.


DCP-AADCP


Correlation


Test


Configuration.


. . . . . . 131


. . . . . . 132


. . 151










5.10


Sand


Arithmeti


Correlation


DCP


AADCP


Instruments..........


. ... 154


11 Silty
AADCP


-Sand


Arithmeti


Correlation


of DCP


and


Instruments


5.12


Penetration


Index


from


AADCP


and


DCP


Instruments


(Maguire


Field)...


157


5.13 Number


Blows


Versus


Depth


AADCP


and


DCP


Test


Instruments


at Maguire


Field....


... 158


AADCP


and


(Maguire


DCP


Estimations


CBR


Versus


Field)


Depth
S.......... 159


15 Number


Different


Blows
Blow


Versus


Rates


Depth


Using


at Maguire


Two


eld.


. . 160


Kanapaha


Boring


Log


SPT-


near


site


#16.


..... 170


FDOT Test

Manual DCP


RAP


Blow


Profil


Profile


of Site


Site


Field


and


Theoretical


Disper


sion


Curves.


Shear


Wave


Velocity


Profile


of Site


#6..


Maximum

Maximum


Shear


Young


Modulus


s Modulu


Profile

s Profil


of Site


of Site


FDOT


Test


Pit


Dispersion


Curve


RAP


Material


182


Proposed


Seismi


Surveying


Configuration...


189


Cummulative


Dispersion


Curves


Over


Several


Survey


Stations


Force


Measurement


Equipment.


Velocity-Time


Force-Time

Energy-Time


Plot.


Plot.

Plot


I


. . 179


. . . . . 263


I


m J














Abstract


of Dissertation


the University
Requirements


Presented


of Florida


the


Degree


to the


Partial Fu
of Doctor


Graduate
lfillment


School


the


Philosophy


DEVELOPMENT
PENETROMETER


OF AN AUTOMATED


(AADCP)


PROTOTYPE


AIRFIELD


AND


THE


DYNAMIC


CONE


EVALUATION


UNSURFACED


AIRFIELD


SEISMIC


SURVEYING


USING


SPECTRAL


ANALYSIS


OF SURFACE


WAVES


(SASW)


TECHNOLOGY


David


Weintraub


December


1993


Chairperson:


Major


John


Department


David


: Civil


son


Engineering


The


of U.S.


Air


Force


Combat


Controllers


infiltrate


unused


airfields


enemy-controlled


territory,


access


report


conditions,


and


control


the


airdrop


the


entrance


the


main


army


force.


Once


the


airfield


secure


limited


, a specially


portable


trained


testing


evaluation


equipment,


team


evaluates


, carrying


unsurfaced


airfield


possible


use


as a landing


zone.


The


equipment


used


to evaluate


the


bearing


capacity


the


airfield


the


Dynamic


Cone


Penetrometer


(DCP)


Empirically


based


relationships


are


used


to predict


the


type


and


number


aircraft


passes


on the


unsurfaced


airfield


based


on inputs


from


the


DCP.


- -


It *


I I


rl


1


L*









develop


prototype


airfield


bearing


test


equipment


that


less


labor


intensive


than


the


currently


used


Dynamic


Cone


Penetrometer


(DCP),


while


still


providing


accurate


bearing


capacity


data,


and


evaluate


Spectral


Analysis


of Surface


Wave


(SASW)


technology


as a means


of seismically


surveying


unsurfaced


runways


and


aprons.


An Automated


Airfield


Dynamic


Cone


Penetrometer


(AADCP)


prototype


was


developed


measure


unsurfaced


airfield


bearing.


Using


correlations


with


the


manual


DCP


and


DCP-CBR


relationships


established


the


literature,


the


AADCP


can


predict


airfield


bearing


strengths.


The


AADCP


was


shown


be inherently


ess


labor


intensive


than


the


manual


DCP


due


pneumatic


operation.


Though


the


AADCP


field-


ready


due


weight


and


power


restrictions,


a viable


prototype


which


can


be modified


to meet


field


conditions.


In addition,


SASW


surveying


techniques


were


successfully


used


to qualitatively


detect


soft


layers


at a soil


site


and


a surveying


technique


was


recommended


to qualitatively


compare


profiles


an unsurfaced


airfield.
















CHAPTER


INTRODUCTION


Problem


Statement


One


the


greatest


attributes


of a modern


air


force


ability


go anywhere,


time,


with


the


utmost


speed.


In the


last


decade,


the


United


States


Air


Force


carried


Grenada


doctrine


1981


with


to Panama


tremendous


1985


skill.


recent


From


Operation


Desert


1991,


our


air


force


has


shown


that


with


proper


training


, equipment


and


leadership


"quick


reaction


strike


forces"


can


do the


job.


In support


these


strike


forces


a team


known


the


Combat


Control


Team


(CCT).


The


mission


U.S.


Air


Force


Combat


Control


Team


infiltrate


unused


airfields


enemy-controlled


territory


without


being


detected,


access


and


report


airfield


conditions,


and


control


the


airdrop


the


entrance


of a main


army


force


(MACP


50-5


1989).


The


airfield

runway e


conditions


valuation


are


teams,


assessed

carrying


specially


limited


trained


portable


CCT


testing


equipment.


Field


test


results


are


used


as input


data


S a -- a -


* 1 -


I -


I


I


rl i i










PAST


DESCRIPTION


AND


PRESENT METHODS


PHASE


RAW AIRFIELD DATA
OBTAINED USING FIELD
EQUIPMENT


FIELD CBR KIT
ACP
DCP


PHASE II


FIELD DATA ENTERED
INTO CBR-DCP
EMPIRICAL MODEL TO


OBTAIN CBR


KLEYN 1975
LIVNEH 1987
HARISON 1989
WEBSTER et al.


PHASE III


ESTIMATED CBR ENTERED
INTO EMPIRICAL MODEL
USED TO PREDICT NUMBER
OF AIRCRAFT TAKEOFF AND
LANDINGS


TURNBULL et al.


1961


LADD & ULERY 1967
HAMMITT 1970


1992












basic


outline


which


describes


the


unsurfaced


airfield


evaluation


process.


The


U.S.


Air


Force


has


primarily


used


two


different


bearing


portable


strength


penetrometer


landing


devi


sites


ces

the


to evaluate


last


decade.


They


are


the


Airfield


Cone


Penetrometer


(ACP)


and


the


Dynamic


Cone


Penetrometer


(DCP).


The


Airfield


Cone


Penetrometer


(ACP)


was


first


used


this

cone


capacity

assembly


the


that


early

pushe


1960s.

d into


This

the a


device


round


uses a

hand.


i rod-

The


ACP


measures


the


cone


resistance


using


a spring


loaded


mechanism


to a depth


of about


inches


but


can


penetrate


deeper


necessary.


However,


ACP


penetration


limited


provide.


the


vertical


At times,


the


force

CCT m


which


ember


a CCT


member


forced


can


to hand


auger


through


a stiff


layer


near


the


surface


and


then


continue


ACP


testing


final


test


depth,


usually


inches.


August


of 1986,


a C-130


aircraft


punched


through


unsurfaced


a Combat


landing

Control


zone

Team


which

(CCT)


had


been


using


previously


the


approved


ACP


evaluation


device


Although


there


were


several


reasons


the


punch-through,


inability


the


the


CCT


two


member


of most


importance


to penetrate


the


where


full


the

inches


using


ACP


device


and


the


limited


number


tests


due












change


occurred


when


the


airfield


constructors


placed


strong,


lightweight,


porous


gravel


over


weak


silt


material


to provide


strength


their


aircraft.


Penetrometer


measurements


to a depth


of 24


inches


inch


intervals


would


have


revealed


the


problem


(soft


layer)"


(Brown,


personal


communication).


Since


this


incident,


the


Air


Force


searched


alternative


field


equipment


measure


bearing


capacity


of a landing


zone.


Today


state-of-the-


art


equipment


used


the


U.S.A.F.


to evaluate


the


bearing


capacity


airfield


the


Dynamic


Cone


Penetrometer


(DCP)


The

weight,


Dynami

mobile


Cone


testing


Penetrometer


device.


a relatively


It consists


light-

.6 pound


sliding


weight


hand


raised


inches


and


released


strike


an anvil-rod-cone


assembly.


This


energy


drives


attached


inch


into


the


ground.


The


cone


inches


diameter


and


has


a 60 degree


cone


apex.


The


number


inches


per


blow


defined


as the


DCP


index


value


a measure


of bearing


strength.


used


the


correlations


to estimate


the


number


safe


takeoffs


landings


unsurfaced


airfield.


The


has


been


used


Air


Force


successfully


the


past


six


years


However,


does


have


some


drawbacks.











procedures


foot


provide


offsets


testing


centerline


at 200


on the


foot


stations


airfield.


With


along


such


data


locations


tested,


under


strict


time


constraints,


sible


that


the


members


will


leave


the


airfield


without


a full


picture


bearing


strength.


The


U.S.


Air


Force


therefore


requested


that


research


be conducted


to address


problems


of field


testing


of unsurfaced


airfields.



1.2 Obiectives


To improve


technology


evaluations


of unsurfaced


airfields,


a large


research


effort


has


been


undertaken


AFCESA/RACO.


The


major


thrust


U.S.A.F


research


was


awarded


the


late


1980


s to Technion


Israel


Institute


Technology


- Transportation


Research


Institute


(TRI).


goal


predicting


improve


the


the


carrying


technology

capacity


of evaluating


unsurfaced


and

airfields.


They


have


emphasized


accuracy


the


correlations


used


to predict


the


number


takeoff


and


landings


and


are


presently


including


aircraft


braking


and


turning


stresses


into


the


unsurfaced


airfield


evaluation


process.


Essentially,


Israeli


effort


to update


the


second


third


phases


shown


in Figure


using


modern


testing












process.


In January


1991


, HQ


AFCESA/RACO


Tyndall


AFB,


requested


new


that


methodologies


a research


effort


to evaluate


bearin


undertaken

g capacity


propose


of unsurfaced


airfields.


The


following


are


specific


objectives


research


effort


investigate


the


development


an unsurfaced


airfi


eld


prototype


device


that


less


labor


intensive


than


the


currently


used


Dynamic


Cone


Penetrometer


(DCP)


data.


evaluate


the


Spectral


Analysis


of Surface


Wave


(SASW)


technology


variations


as a means


throughout


the


asses


unsurfaced


sing s

runway


ubsurface


and


spatial


apron.


Overview


dissertation


has


been


divided


into


seven


chapters.


The


first


chapter


defines


the


purpose


and


objectives


research.


The


second


chapter


presents


the


reader


with


literature


evaluate


review


carrying


of past


capacity


present


U.S.A.F


of unsurfaced


. methods


airfields.


This


chapter


presents


an introduction


to Spectral


Analysis


of Surface


Wave


(SASW)


technology


and


use


in the


selsmic


evaluation


of soil


sites.


The


AADCP


third


prototype


chapter


development


scusses


and


major


describes


pha


the


ses


final


the


version


w


w --











systems.


The


chapter


then


introduces


the


several


prototypes


developed,


chronological


order,


leading


final


AADCP


design.


Each


prototype


is discussed


detail


and


shown


how


the


final


vers


evolved


from


The


chapter


concludes


with


a detailed


description


the


final


AADCP


equipment,


including


the penetration


device


with


auxiliary


equipment.


The


fourth


chapter


concentrates


on describing


the


equipment


used


research


to accomplish


the


SASW


test


evaluation.


It includes


a discussion


on the


digital


signal


analyzer,


signal


receivers,


and


noise


sources.


The


SASW


evaluation


was


accomplished


with


equipment


purchased


the


Florida


DOT


(Gainesville


Office)


The


fifth


chapter


describes


the


the


results


testing


of field


procedure


testing


esents


the


and


Automated


scusses


Airfield


Dynamic


Cone


(AADCP)


prototype.


chapter


presents


and


discusses


DCP


field


repeatability


and


DCP


and


AADCP


prototype


correlation


testing.


The


sixth


chapter


detail


the


testing


procedure


evaluation


of seismically


surveying


an unsurfaced


airfield


using


the


spectral


analysis


of surface


wave


(SASW)


technology


It discusses


the


site


locations


where


the


evaluations


took


place


, the


testing


procedures


and


test












airfields.


Several


areas


of future


study


are


also


discussed.


There


are


five


appendixes


that


contain


field


data


the


DCP


reliability


testing,


SASW


Kanapaha


testing


results,


AADCP-DCP


correlation


results,


force


measurement


results


and


AADCP


instruction


manual















CHAPTER


REVIEW


OF THE


LITERATURE


Introduction


The


background


purpose


this


on past


chapter


present


to provide


methods


used


the


the


reader


. Air


Force


to evaluate


carrying


capacity


of unsurfaced


airfields.


In addition,


this


chapter


presents


an introduction


Spectral


Analysis


of Surface


Wave


(SASW)


technology


use


seismic


evaluation


of soil


sites.


The


literature


review


begins


with


a discussion


on unsurfaced


airfield


trafficability.


Unsurfaced


Airfield


Trafficabilitv


Introduction


Trafficability


an airfield


determined


the


shearing


strength


the


soil


surface


subsurface


and


somewhat


stickiness


and


slipperiness


the


surface


(Molineux


1955)


the


event


that


shear


strength


exceeded


an aircraft


load,


surface


fails


and


puts


aircraft


at risk


immobility.


In addition,


once


the


S -- -


1












Unfortunately,


impossible


to label


a particular


area


with


a single


trafficability


rating


over


an extended


period


time.


Since


trafficability,


bearing


and


traction


are


based


primarily


on shearing


strength,


they


are,


like


the


strength,


dependent


on time,


weather,


and


location.


A few


cycles


traffic


can


usually


be sustained


on dry


soil


However


, if


moi


sture


added


the


shearing


strength


can


significantly


decreased.


The


magnitude


effect


depends


on the


soil


type.


Generally


fine-grained


soils


silts


and


clays)


will


more


effected


than


coarse-grained


soil


(sands)


Figure


shows


the


effects


of moisture


the


shearing


strength


three


fine-grained


soils.


The


cone


index


defined


as the


stress


(force


over


area)


required


penetrate


a certain


depth.


Notice


Figure


that


as the


moisture


content


increases


, the


cone


index


decreases.


an easy


task


measure


the


trafficability


an airfield


because


there


are


so many


changing


variables


involved


a precise


process.


theoretical


leads


solution


the


virtually


conclusion


impos


that


sible


the


correlative


studies


performed


on unsurfaced


airfield


evaluation


techniques


have


been


empirical


nature.


The


next


section


describes


some


this


work.




































10 40 10 go 100 IN 140


CONE


INDEX


(PSI)











Measurement


Soil


Trafficabilitv


Since


the


late


1940


U.S.


Air


Force


has


sought


after


unique


methods


to rapidly


determine


the


trafficability


of aircraft


on all


types


of soils.


A direct


means


of soil


trafficability


measurement


required


the


safe


landing


of military


aircraft.


Many


methods


have


been


used


the


Air


Force


to determine


insitu


soil


bearing


strengths.


The


two


most


popular


have


been


the


Sub-grade


Modulus


method


California


Bearing


Ratio


method.


However,


these


field


testing


methods


require


an extensive


amount


time


equipment


and


are


thus


applicable


to a fast


pace


war-


time


environment.


A number


of simpler


and


less


time


consuming


methods


have


been


developed


and


tested


over


the


last


to 50


years


as discussed


the


next


section.


Carrvina


Capacity


of Unsurfaced


Airfields


Introduction


In the


early


1960


, the


U.S.


Army


conducted


tests


an effort


to determine


factors


which


effect


the


carrying


capacity


an unsurfaced


airfield


(Turnbull


et al.


1961).


The


study


concluded


that


capacities


should


be based


on the


number


coverages


an aircraft


to failure.


Failure


was


defined


as 1.5


inches


of elastic


deformation


and


inches












pressure


were


the


factors


which


effect


the


number


coverages


to failure.


Correlations


were


then


developed


using


weighted


carts


, with


specific


tire


pressures


and


aircraft


loads,


building


, medium


and


high


CBR


test


sections,


and


measuring


the


number


passes


to failure.


Figures


landmark


display


study.


Figure


some

shows


the


that


results


an aircraft


this

with


tire


pressure


of 60 psi


and


a 30-kip


single


wheel


load


can


operate


passes


on an unsurfaced


airfield


with


a CBR


6.6.


Since


studies


have


original


been


1961


completed.


study,

Moshe


several

Livneh


correlation

(Israeli


Institute


of Technology),


Capacity


1989


of Unsurfaced


draft


Runways


report


Low


Volume


"Carrying

Aircraft


Traffic,


compares


several


different


design


curves


used


to estimate


number


of aircraft


passes


allowable


a C-130E


Hercules


aircraft.


Figure


is a collection


design


that


curves


the


gathered


selection


Livneh


of a design


s research.


curve


Linveh


very


points


critical


the


outcome


design.


example,


Figure


selection


of a CBR


of 6 with


a 125


kip


load


reveals


the


number o

goals of


passes


Livneh


to be 1.5,

s research


or 90.


to verify


It is


and


one


update


the


these









































*I aw.L TISM liU -I t.5 3 a O0 is LA&b
ElbtiE e*ta8 eAS meawsM ee Musseft Geos mnatas


* a

- 5

V I


:r
|1 I
as
a





y
-I.





-. 1j
-e
-1



Z
-e



-a 3
I
-l


Figure


Design


Curve


The


Single


Wheel


Carrying


Capacity
(Turnbull


a *e S We


of Unsurf


ace


d Runways


et al. 1961)


u
*
MI.

3
I


a
- I



" 3

~*
'3u


* T r *f
MUr f il ir U


m









































ESWL 28 kips tire press


2 13 ( 10 0 0 0 0 O 1M00 200


Reference


Author


Turnbull


Womack
Ladd 1


et al.


1961


1965


965











detail


used


the

the


two n

U.S.


lost

Air


popular

Force


portable


measure


insitu

the b


test


hearing


methods

strength


of unsurfaced


airfields.


They


are


the


Airfield


Cone


Penetrometer


(ACP)


and


Dynamic


Cone


Penetrometer


(DCP)


The


measured


field


bearing


strength


then


correlated


with


California


Bearing


Ratio


(CBR)


test


to allow


the


CCT


member


to enter


the


design


nomograph


determine


a number


passes.


information


These


on each


descriptions


instrument


will


and


include


include


background


major


advantages


disadvantages.


Airfield


Cone


Penetrometer


LACP)


The


Airfield


Cone


Penetrometer,


Figure


, was


designed


measure


the


bearing


capacity


of soils


which


support


ACP


the


provides


operations


of aircraft


an investigator


a soil


as well

index


as vehicles.


called


Airfield


Index


(AI).


This


a measure


the


bearing


capacity


the


soil


tested


and


then


correlated


with


the


California


Bearing


Ratio


(CBR).


The


ACP


a hand-probe


type


instrument


consists


of a 30 degree


right


circular


cone


with


a base


diameter


of 1/


inch


inch


long,


inch


diameter


rods.


A housing


near


the


top


the


ACP


contains


an intertwined


tension


spring


and


a load


indicator


a load























SPRING


3/8" ROD


30 DEGREE
CONE APEX












Five


penetrations


at each


location


an "X"


configuration


are


made


with


a depth


of penetration


of at least


inches.


Figure


2.6 shows


correlations


vs CBR


various


soil


types


(Fenwick


1965) .


The


long-dash


dark


line


this


figure


represents


the


currently


used


relationship.


applies


to both


cohesive


granular


soils


and


has


equation:


CBR


= -0.22


+ 1.10


(log


AI + 0.13)


The


ACP


was


used


the


Air


Force


measure


bearing


capacity


from


the


mid-1950s


to the


mid-1980s.


However,


device


had


a number


limitations.


The


first


limitation


relates


the


correlation


the


and


CBR


values.


Livneh


and


Ishai


(1989)


made


a study


the


confidence


intervals


these


correlations.


The


confidence


interval


used


determine


the


probability


that


the


stated


correlation


within


a certain


range


of results.


If a normally


distributed


population


assumed,


a 95%


confidence


interval


equal


to +/-


Log


This


essence


means


predicted


value


of Y


, the


range


between


7(Y)


and


(Y)/2


Therefore,


a 10 CBR


predicted


the


ACP,


there


a 95%


probability


that


the


actual


CBR


value


within


the


range


to 40.


Such


a range


corresponds


number


of aircraft


passes


somewhere


between


zero


and


one


































































1 2 3 4 5 6 7


8910












significantly


mislead


when


used


to determine


a predicted


coverage


value.


A second


limitation


the


ACP


was


the


accuracy


the


values


on the


nomographs


which


were


compiled


more


than


years


ago


using


outdated


aircraft


tire


configurations.


In addition,


the


nomographs


do not


take


into


account


the


braking,


turning


and


thrust


stresses


that


are


applied


modern


aircraft.


A third


limitation


concerns


CBR


range


the


ACP


which


from


zero


to 15.


This


means


that


the


ACP


cannot


cover


entire


range


of normal


unsurfaced


airfield


values


which


between


CBR


values


of 3


to 30.


This


last


limitation


somewhat


the


culprit


the


1986


Operation


Blast


Furnace


accident


where


was


found


that


the


ACP


could


penetrate


through


a stiff


layer


of material


overlaying


soft


clay.


Although,


there


were


other


reasons


the


punch


through


the


landing


gear,


inability


the


ACP


penetrate


a stiff


layer


was


high


on the


list


(Brown


1986).


an effort


overcome


these


limitations,


the


U.S.


Air


Force


switched


the


mid


1980


s to the


Dynamic


Cone


Penetromete

unsurfaced


(DCP)


airfields.


measure


carrying


In addition,


the


capacity


Technion-Israel


Institute


f Technology


Transportation


Research


Institute











ensure


a high


degree


of reliability.


The


objectives


included


(Livneh


Ishai


1989)


development


an improved


design


nomograph


correlated


with


operational


landings


C-130E


aircraft


simulation


other


aircraft


using


large


scale


wheel


-track


testing


mobility


number;


development


a carrying


capacity


model


which


includes


effects


of remolding


characteristics


of soil,


braking


, reverse


thrust


turning


operations;


and


application


of Dynamic


Cone


Penetrometer


(DCP)


technology


to accurately


determine


soil


strength


field.


Dynamic


Cone


Penetrometer


(DCP)


.1 Introduction


the


last


seven


years


the


U.S.


Air


Force


has


adopted


the


Dynamic


Cone


Penetrometer


as the


preferred


light-weight


bearing


capacity


testing


devise.


In general,


the


advantages


DCP


are


cheapness,


simplicity


capability


providing


rapid


measurement


situ


strength


of subgrades


a non-destructible


manner


(Harison


1989).


The


original


DCP


developed


insitu


CBR


Scala


of cohesive


1956


soils


was


(Scala


used


to evaluate


1956).


Today,


the


the











Smoltczyk


1982).


Penetrometers


used


continuous


dynamic


testing


were


divided


into


four


basic


categories


depending


size


the


hammer


dropped


Table


.1 shows


the


arbitrary


classifications


four


categories


The


DCP


used


Air


Force


falls


into


the


"DPL"


light


category


since


has


an 8 kg


hammer.


DCP


Description


The


DCP,


adopted


the


U.S.


Air


Force,


consists


mm diameter


steel


rod


with


a cone


one


end


driven


attached


falling


weight


at the


other


end,


Figure


The


angle


cone


is 60 degrees


and


the


base


diameter


mm.


The


additional


mm on the


cone


was


designed


to prevent


resistance


to penetration


along


the


mm steel


rod.


The


DCP


uses


a sliding


8 kg


hammer


falling


mm to drive


the


cone


to a depth


to 1 meter.


Two


people


are


required


to operate


the


DCP.


One


person


lifts


drops


weight


while


the


the


test,


other


a plot


measures


the


the


number


depth


of penetration.


of blows


versus


During


depth


recorded,


Figure


The


number


inches


per


blow


defined


as the


DCP


value.


This


value


then


also


used


correlate


test


the


CBR


test.




















Table


Classification
Penetrometers


of Continuous


(Melzer


and


Dynamic


Smoltczyk


Cone


1982


TYPE ABBREVIATION MASS (KG)


LIGHT DPL < 10





MEDIUM DPM 10 40





HEAVY DPH 40 60





SUPER HEAVY DPSH > 60





























B. HAMMER







WO PARTS









MEASURING


MASS







SCREW


TOGETHER


TAPE


CONE


r


*


m












NUMBER


BLOWS


(DCP)


(DCP)2 Lh2






A\ 3
(DCP)3




(DCP)4












unsurfaced


runway


One


those


factors


was


the


bearing


capa


city


airfield


as measured


the


California


Bearing


Ratio


(CBR)


test


test


, developed


the


California


Division


of Highways


and


later


adopted


the


U.S.


Corps


Engineers,


was


most


widely


known


strength


test


used


the


1950


The


test


involves


using


a standard


piston


to penetrate


a specimen


inside


a mold


the


laboratory


after


soaking


4 days.


The


load


at 0


or 0


inches


of penetration


compared


the


load


required


penetrate

is known


a standard


as the


specimen


California


the


Bearing


same


ratio.


depth.

Later


This


ratio

test


was


adapted


into


a corresponding


field


test.


The


same


ston


dimensions


were


used


and


insitu


bearing


measured


different


depths.


However,


the


field,


reaction


frames


were


mass


required


of a large


the


unique


the


truck


combat


piston


was


to push


used


control


against.


Often


reaction.


ssion


where


Because


timing,


secretiveness


and


mobility


were


paramount,


large


reaction


frames


could


not


be used.


Therefore,


Airfield


Cone


Penetrometers


and


Dynamic


Cone


Penetrometers


were


used


measure


a type


of bearing


capacity


as di


scussed


the


previous


sections.


A correlation


required


to bridge


gap


between


the


known


bearing ca


pacity


in terms


the


DCP
















Tabl


International


Comparison


the


Equation


Log


CBR


- B(Log


DCP)


(Livneh


and


Ishai


1989)


"Typ of tertias


Cnutry of Oigin


2.556 1.145 1 AU tLyps kAtre rU
2.810 1.328 1 Al types rdrmia

2.668 8.318 1 S Austrati

2.349 9.868 I Law clys Astraia
1.9s5 8.726 1 Intnmodiate clay Astrsaia

2.378 .9414 i Cay Australia
2.497 1.29 1 SiLts ad clays Aistralia
2.849 1.210 1 Silts AatraiaU
2.389 8.973 1 HiV* clyr Astralia

2.555 1.135 1 Smpit o-fin d &gand
in C iR nul&
2.756 1.135 1 U nMf ird srplts island

2.948 1.169 1 Sub B- Er1adl S

3.178 1.415 1 &w Ergland SQdan
2.222 9.756 1 E rrr cLys Englad Snt

3.973 1.239 1 t mwiw clays Eglnd n
2.20 .710 1.5 A types IsrC t

2.317 9.8577 1 A typs Sun Ergad
2.589 1.31 1i A typ hB1gium

2.398 1.26 1 A typ. u rple South Africa
oonfitnd in R mould
2.865 1.269 1 AU typ, South Africa
Surm f irdi sapI
| ~i


= A











use


today.


In general,


they


have


the


form


Log


CBR


= A


- B(Log


DCP)


c (2


where


CBR
DCP


= California


= DCP


index


Bearing


Ratio


percent)


value


= constant
= constant
= exponent


Some


more


generally


accepted


relationships


are


listed


Table


along


with


the


type


testing


procedure.


Figure


shows


several


those


CBR-DCP


correlations


a graphical


format.


The


laboratory-based


research


involves


preparation


two


identical


samples


with


the


same


water


content,


compactive


effort,


and


mold


size.


The


samples


are


subjected


to a circular


steel


surcharge


weight


with


a hole


the


center.


This


allows


penetration


the


piston


CBR


test


and


cone


tip


the


DCP


test.


Normal


procedures


are


used


run


the


CBR


and


DCP


tests.


Harison


(1986)


found


that


soaking


the


samples


had


an insignificant


effect


on the


CBR-DCP


relationship,


changing


the


moisture


content


and


dry


density


also


did


not


affect


the


relationship


that


a Log-Log


representation


was


more


suitable


than


inverse


model.
















Table


Common


CBR-DCP


Relationships


REFERENCE
TEST
CBR-DCP EQUATION


Kleyn


1975


Laboratory Testing


Log CBR


.27(Log


DCP)


Smith and Pratt


Field


(1983)


Testing


= 2.56


- 1.15(Log


DCP)


Livneh


(1987)


Laboratory Testing


Log CBR


= 2.20


- 0.71(Log DCP


^1.5


Harison


1989


Laboratory Testing


- 1.14(Log


DCP)


Webster


et al.


(1992)


Field


Testing


Log CBR


= 2.46


- 1.12(Log DCP)


CBR


1


I


I


I


1


_~~ __ ____ _I ii I //i3

























CBR,%


1 2 3 4 5 10 15 20 30 40 50 100


DCP


mm\blow


WES DATA
0


UVNEH (1987)
,Ca *I Cp C Cl CC Si 1


HARISON (19 7)
b + mlmotO


VAN VUUREN (1969)


KLEYN (1975)











that


laboratory-based


CBR


tests


of granular


materials


give


higher


CBR


results


than


tests


carried


out


in the


field


(Livneh


Greenstein


1978).


This


variation


due


to the


geometry


testing


mold


and


the


specimen


preparation


procedures.


Figure


shows


the


assumed


failure


mechanism


the


plunger


in the


laboratory


field.


the


laboratory,


the


failure


plane


obstructed


the


sides


mold


which


increases


resistance


to the


plunger.


In addition,


lateral


precompression


specimen


during


compaction


procedures


contributes


to the


increase


CBR


results.


Figure


demonstrates


effect


increase


mold


diameter


and


reductions


CBR


value


(Metcalf


1976)


Based


on these


results,


some


design


agencies,


including


the


Corps


of Engineers,


have


introduced


other


procedures


estimating


CBR


design


values.


The


Corps


of Engineers


relates


plasticity


and


gradation


granular


base


CBR


values.


Livneh


Greenstein


(1978)


suggest


using


theoretical


derivation


based


on a modified


CBR


test


which


controls


lateral


pressure.


A third


method


to simply


measure


the


field


CBR


values


using


either


the


DCP


and


correlation


the


CBR


or using


the


field


CBR


test


procedure


which


is considered


to be destructive


and


very


time










































SP


ZOne


r


q4-


zone 2


"- ^


u1 uuu


















300



200


100



0


2 4 6


plasticity


index,












proving


ring,


penetration


piston,


dial


gages,


surcharge


weights


deflection


beam.


Figure


shows


the


apparatus


assembled.


Using


a stop


watch


and


dial


gages,


the


piston


jacked


into


soil


at 0


inches


per


minute.


Proving


ring


readings


are


taken


at 0.025


inch


increments


a final


penetration


of 0.5


inches.


Tests


correlating


insitu


CBR


and


DCP


have


been


conducted


Smith


and


Pratt


1983.


Their


relationship


expressed


Log


CBR


(Log


DCP)


and


extremely


close


to Harison


(1989)


laboratory


CBR-


relationship


which


was


modified


to include


the


confining


effect:


Log


CBR


(Log


DCP)


This


suggests


a greater


level


of confidence


between


the


field


and


laboratory


correlations


the


CBR-DCP


relationships


than


previously


thought.


major


advantage


of using


the


DCP


over


the


field


CBR


the


decrease


amount


time


takes


run


a DCP


test


versus


a CBR


test.


However,


the


reliability


the


the















Livneh


and


Ishai


(1989),


have


tested


degree


repeatability


both


have


concluded


that


the


DCP


more


repeatable


than


the


field


CBR


test.


The


measurement


used


compare


the


test


s repeatability


coefficient


variation


the


ratio


standard


deviation


mean.


Smith


Pratt


(1983)


concluded


that


the


coefficient


variation


of field


CBR


a material


was


around


percent

percent.


while


that


Livneh


and


the

Ishai


laboratory

(1989) re


was


ported


around


lower


values


shown


Table


The


maximum


coefficient


of variation


obtained


field


was


23 percent


while


maximum


the


CBR


test


was


32 percent.


This


section


has


presented


a number


of empirical


CBR-


DCP


correlations.


the


following


section


discussion


presented


on mathematical


models


used


describe


penetration


of a DCP.


.4 Dynamic


Cone


Penetrometer


Mathematical


Models


The


accepted


model


used


to represent


CBR-DCP


relationship


the


log-log


model.


can


be derived


from


the


rational


pile


formula


discussed


J.E


. Bowles


(Bowles


1988).


This


formula


basi


nearly


all the


pile-


(CV),














Table


Variance
(Livneh


Coefficient Values
and Ishai 1989)


CBR


and


DCP


Tests















I= Fdt


where


= impulse

= force

= time


Momentum


the


product


mass


velocity


and


expressed


as:


= my


where


= momentum


= velocity


= mass


The


principle


of linear


impulse


and


momentum


defined


the


initial


momentum


plus


the


impulse


equals


the


final


momentum


and


expressed


as:


Lini trial
mt v,)


+ Impulse
+ fFdt =


= Lfinal


m(v,)














[(W


x (H)]


[(W) + (e2XW2)


( w+ww,)


where


point
weight
weight
height


res


instance


of hammer


instruments


of hammer


fall


penetration
coefficient


Note


simplic


: Only


ity;


impact
other


sses
sses


depth


res


are


might


titution
included
include


Equation


: rod


loss and


soil


oss.


closer


inspection


pile


driving


equation


and


some


separation


terms


reveal


work-energy


theorem:


(Energy


(Work


Out)


(Impact


Losses)


x H)


= (R


x D)


+ [w


(1-e2


The


point


res


distance


value,


a measure


the


strength


the


material


tested.


Therefore


, it


is assumed


that


a function


of other


strength


parameters


such


as CBR


and


therefore


following


equation


can


be written:


CBR


= A


.10)












losses


such


as impact,


the


equation


might


be re-arranged


CBR


.11)


Log


CBR


= Log


- B


x Log(D)


.12)


Equation


now


the


commonly


used


form


express


the


CBR-DCP


relationship.


Equation


called


inverse


model


has


been


used


Smith


and


Pratt


(1983)


express


CBR-DCP


relationships.


However,


Equation


not


commonly


used.


One


aims


of Livneh


Ishai


(1989)


research


was


to search


literature


a theoretical


derivation


which


would


relate


the


DCP


values


with


the


basic


soil


strength


properties


of cohesion


and


angle


internal


friction


The


theoretical


derivation


used


to verify


the


empirical


The


correlation


test


between


consists


CBR


of dropping


and


DCP.


a 17.6


Ib weight


inches


onto


an anvil.


The


anvil


connected


to a 39


inch


vertical


rod


and


cone


assembly


that


penetrates


the


unsurfaced


airfield.


The


fundamentals


of dynamics


show


that


the


maximum


amount


of dynamic


energy


from


one


blow


the


DCP


dE = W


x h


.13)


where


= A


(D)-B












Due


to friction,


heat


other


energy


losses,


the


entire


potential


energy


does


not


reach


the


DCP


cone


tip


Therefore,


Livneh


et al.


(1990)


describe


the


s apparent


energy


transfer


efficiency


factor


as:


.14)


where


= quasi-static


energy


one


blow


= apparent


energy


transfer


efficiency


factor


In other


words,


n is


a measure


of how


well


the


DCP


transfers


energy


the


cone


tip.


Livneh


et al.


(1990)


conclude


that


the


n value


test


between


0.50 based


upon


several


correlation


investigations.


The


total


quasi-


static


energy


(Ei)


given


x h


x n


.15)


where,


= total


number


of blows


Using


Schmertmann'


(Schmertmann


1979),


paper


Livneh


on "Statics


wrote


the


basic


SPT"


equilibrium


equation


x H


x N


x n


.16)


where


= depth


penetration


= quasi-static


force


required


cause


= W


= L











Livneh


presents


the


following


correlation


x h


x n)


.18)


x 22


x 0.45)


= 179


where


DCP


given


in/blow


given


can


seen


that


the


force


the


key


to determining


relationship


between


DCP


and


the


cohesion


and


angle


internal


friction


the


soil


Theoretical


derivations


based


on either


cavity


expansion


theory


or on plastic


failure


theory


are


used.


Rohani


and


Baladi


(1981)


present


a failure


model


the


relationship


between


Cone


Index


(CI)


and


the


material


strength


characteristic


based


on cavity


expansion


(Vesic


1972


an infinite


soil


mass


and


on the


empirical


assumption


that


the


cone


penetrometer


shears


the


surrounding


soil


during


penetration


process.


The


theory


combines


shear


expanding


strength


spherical


expression,


cavity


internal


an unbounded


pressure


elastic-plastic


medium,


the


geometry


of a penetrating


cone


to derive


express


sion


CI for


granular


and


cohesive


material


comparison


of calculated


and


the


measured


values


shows












L = 1.48
D = 0.799








#


in
in


20 40 60


ASURED CONE


INDEX,















.48


799


in
in o



0 0

00


0 50 100 150 200 250


iASlRMED CONE INDEX. PSI


















COt ZNDOf,


LEGEND


DATA


C--- a


PREDICTION


799


VERY DOISE


SAND


LOOSE SAW











penetrate

Mitchell


a DCP

(1974)


cone,

They


was introduced

used Meyeroff


Durgunoglu


"Ultimate


and


Bearing


Capacity


of Wedge-Shaped


Foundations"


(Meyerhof


1961)


research


The


failure


surface,


shown


Figure


.16,


closely


represented


the


failure


planes


observed


using


wedge


shaped


penetrometers


at shallow


depths.


Using


observed


failure


mechanism


and


equilibrium


analysis


the


failure


zones


, a penetration


resis


tance


equation


can


be written:


[B,(N, ) (Eq) ]


.19)


where


= ultimate


unit


tip


resistance


= unit

= mass


cohesion

density


= penetrometer


diameter


and


= penetration


resistance


factors


E, and


= shape


factor


Figure


shows


fairly


good


agreement


of friction


angles


predicted


using


penetration


resistance


factors


versus


measured


values


Force


Analvsi


the


Dynamic


Cone


Penetrometer


A method


to generate


force


history


the


DCP


instrument


was


demonstrated


by Chua and


Lytton


(1989)


[c(Ne) (e,) ]















qf


















Jones Beach Sand /
A .= :75' 8/6:0A to 0.5. /8= 7.5
* -cI45'
* =4:7.5 1/ :0.4 to 0.5.D/, B/ 5.2

m//
.J/


/








I/I-I-I-I_ .,-I


PREDICTED


-deg














ACCELEROMETER


HANDLE


HAMMER (17.6 Ibs./8 kg)


(0.12"/3mm)


THE


CONE


CONE ANGLE


60*


(1.14'/29mm)


UPPER SPRING CLIP

0.683/16mm #STEEL ROD



MEASURING ROD WITH
ADJUSTABLE SCALE

-LOWER SPRING CLIP
- CONE












the


impact


hammer.


integrating


the


acceleration-time


displacement-time


signal,


the


historic


velocity-time


were


generated.


and


Figure


shows


course


these


signals


material.


a test


Using


performed


a computer


program


a granular


that


base


model


dynamic


response


under


load


the


force


history


sliding


hammer


onto


the


anvil


were


generated.


Figure


shows


triangular


shaped


force


impul


ses


estimated


matching


measured


and


calculated


acceleration


signals.


Stress


Wave


Propacation


When


a rod


suddenly


struck


a force,


, at


one


end


time,


then


at the


first


instant


time,


particles


are


still


at rest.


very


short


time


later


, dt,


section


speed


the


or wave


rod,


compressed


propagation


velocity,


an amount,


can


wave


be defined


= dL/dt


.20)


The


wave


speed


the


speed


with


which


a compression


tension


zone


moves


along


a rod.


The


deformation


of a point,


can


also


be written


(F)(dL)/(A)(E)


.21)


where


= area


of rod









































S 5.M 5W4 St00 LaU C0 .01
lugU-


I tS4 SAM .00oe 0.01 .012
Tug (c-eOu


g L.m .a e.e.m ea.01 t U.ls
nuC (SCOlms




















































0 0.002 0.004 0.001 0.008 0.01 0.012


TIME (SECONDS)









53

(F)(dL)/(A)(E) (dt)


(F)(


c)/ (E)(A)


The


partic


speed


the


speed


with


which


a particle


rod


moves


as a wave


passes


The


acceleration


thi


point


= dv/dt


.23)


(F) (c)/(E) (A)(dt)


From


Newton


s Sec


Law


definition


mass


(m) (a)


.24)

.25)


(dL) (A)(p)


where


= mass


density


then


(dL)(A)(p)[(F)(


c)/(E)(A)(dt)]


or by


canceling


out


F and


.26)


The


wave


speed


a function


the


material


properties


rod


which


travel


The


stress


penetration


rod


= F/A


.27)

.28)


= Ee


where


, m,











Using


Equation


and


re-arranging


velocity,


the


stress


.30)


[E] [dd/(c) (dt) ]


[(E) (v)]/[c]


Multiplying


the


stress


area


the


rod,


.31)


term


EA/c


called


impedance,


and


calculated


using


Young


s modulus,


cross


sectional


area


the


rod,


the


wave


speed


from


Equation


.26.


This


term


implies


that


the


rod


offers


a resistance


or impedes


the


change


velocity.


Equation


suggests


that


the


particle


velocity


penetration


rod


can


be measured,


then


the


force


in the


can


be determined.


An accelerometer


used


this


purpose.


An accelerometer,


mounted


penetration


rod,


and


an oscilliscope


are


used


measure,


record,


and


integrate


acceleration-time


signal.


The


integration


signal


reveals


a velocity-time


plot


which


can


then


used


to plot


a force-time


graph


penetration


rod.


This


plot


would


similar


to Figure


2.20.


Other


Dynamic


Cone


Penetrometers











The

consists


Dual


Mass


same


DCP,


invented


basic


dimension


Webster

s as the


et al. (1992),

standard DCP


except


that


the


mass


can


be either


or 10.1


Ibs.


The


mass


is converted


from


to 10.1


removing


an outer


steel


sleeve


attached


a set


screw.


Webster


reports


that


the


cone


penetration


one


Ib blow


hammer


about


twice


that


the


10.1 ib


blow.


The


purpose


dual


for

more


hammer


stiff


weight


materials


suitable


and


that


the


whereas


yields


Ib hammer


10.1


better


hammer


results


is best


was


soils


suited


found


of CBR


less


than


ten.


The


testing


procedure


also


the


same


as the


standard


DCP


except


that


the


DCP


index


derived


from


the


10.1


Ib hammer


index.


multiplied


In addition,


two


a specially


to equal


the


designed


standard


disposable


cone


was


designed


to reduce


the


effort


removing


the


DCP


from


the


ground.


The


cone


remains


ground


after


testing


and


replaced


before


each


success


test.


Webster


concludes


that


this


disposable


cone


can


double


the


number


tests


per


day.


The


Automated


DCP,


invented


Livneh


et al.


(1992),


consists


of a mobile


air


compressor,


a falling


weight


mechanism,


a lifting


and


release


mechanism


and


a penetration


rod.


Basically,


the


system


uses


compressed


air


to raise












to those


produced


the


manual


DCP.


He concludes


that


automated


device


fully


recommended


as an efficient


substitute


the


manual


device,


from


the


point


view


both


precision


and


technical


testing.


Livneh


also


reported


that


statistical


analysis


demonstrated


that


automated


Dynamic


Cone


Penetrometer


results


were


independent


blow-rate


range


of 24


to 40 blows


per


minute.


Forty


blows


per


minute


was


the


fastest


practical


rate


tested.


Aerial


Penetrometers


Because


inaccessibility


some


landing


sites,


to hostile


enemy,


rough


terrain,


insitu


time


testing


restraints,


aerial


penetrometers


have


been


developed


measure


bearing


capacity.


Since


the


early


1940s


, the


Department


of Defense


investigated


projectile


devices


launched


One


from


earliest


to improve


the


investigations


penetration


studied


the


of bombs.


penetration


a cannon


ball


into


earth


revetments.


Using


projectile


bombing


technology,


the


Air


Force


Cambridge


Research


Center


developed


an aerial


penetrometer


measure


bearing


capacity


remote


sites.


The


penetrometer


shown


Figure


2.21


was


an aluminum


cylinder


two


feet


long,


one


and


one


half


inches


diameter


and


weighed


two


pounds.


t was


dropped


hand


_





















STREAMER


rumxa


PNKRIOETER SELL
llasana tube, 61 8?
1 j in. o.d. 1/52 in,


wall


FlUR CARTRIDGE (25 i

FLARE RETAINER
Alumima tube, 61 ST


1 1/8 In.


o0d.


IMPAC GAGE
Flat wire spring
FriRir PCT

Supports tap tfla
Allov paasae of
lmwr flaeu



IMPACT GAD

nzImI Pn

frts oGeatr flare
all pasa. e of
bottom flaru


IMPACT GAGE
FIRIW PIN


POCWT


I LARm a


riple Flat
W^A -LA t itL


pe.


Length 2.


S* .>-I


3 ft


w












springs,


ratings,


or shear


pins,


high


ratings,


were


activated


cartridge


was


the


impact


triggered


the


the


ground.


rating


the


A shot-gun


site


type


was


strong


or stronger


than


the


rating


the


penetrometer,


a flare


would


be fired


about


feet


into


the


air


from


the


penetrometer.


When


used


in a water


environment


, such


as a


beach


head,


a dye


would


replace


the


flare.


a pilot


were


to fly


over


a site


dropping


these


proj ectiles,


he would


look


the


flares


to fire


in a consistent


manner


and


would


know


site


was


acceptable


his


aircraft.


In later


vers


ions


this


type


of aerial


penetrometer,


three


different


color


flares


were


used,


indicating


different


cone


indic


es.


some


versions,


a radio


telemetered


indicator


was


placed


inside


the


penetrometer


and


radio


signals


would


be transmitted


back


the


pilot


with


test


results.


The


transmitter


was


capable


transmitting


to four


miles


away


30 minutes


at a time.


the


1960s,


when


technology


allowed


the


projectile


instrumented,


a projectile


was


designed


to actually


penetrate


the


ground,


with


little


deviation


the


line


flight


with


instrumentations


on board


such


as an


accelerometer


measure


decelerations.


The


Sandia


Corporation


was


a major


research


group


that


contributed












The


projectile


would


penetrate


to 300


feet


in soil.


was


found


their


research


that


"for


a given


projectile


impacting


vertically


at a given


velocity,


the


deceleration


depth


depend


on the


properties


the


soil


rock


media


being


penetrated"


(Caudle


et al.


1977).


was


then


surmised


were


that


known


decelerations,


a given


depth


projectile,


and


then


impact


the


velocities


properties


earth


penetrated


could


be determined.


Though


the


aerial


penetrometer


technology


seemed


promising,


several


limitations


prevented


the


program


from


making


large


impact


in the


field.


The


first


limitation


was


the


erroneous


data


provided


to the


pilot


the


projectile


were


to strike


a stone,


clump


moss


, animal


hole


or any


number


of other


obstacles.


Secondly,


number


of penetrometer


required


to accurately


measure


the


bearing


capacity


an airfield


was


estimated


to reach


the


hundreds


the


site


was


a non-homogeneous


soil


with


an area


ft x 1800


(Molineux


1955).


Finally,


the


area


investigated


prevented


full


penetration


the


projectile,


area


would


have


to first


cleared


of projectiles


before


any


landing


operations


could


made.


Seismic


Survevinc











landing


zone.


Today,


the


evaluation


is accomplished


Dynamic C

described


one


Penetrometer


earlier,


can


test


method.


effectively


test


Since

only


this

one 1


method,


location


a time,


seismic


proposed


methods


this


to complement


research


the


use


evaluation.


insitu


Today


seismic


methods


include


the


crosshole,


downhole,


surface


refraction,


reflection


methods


and


spectral


analysis


surface


waves.


Of these


methods,


spectral


analysis


surface


waves


had


potential


of being


most


promising


method


of evaluation.


It precluded


the


use


of destructive


and


time


consuming


borehol


and


provided


a means


evaluation


where


a stiff


material


overlaid


a soft


material.


The


Spectral


Analysis


of Surface


Waves


(SASW)


method


insitu


soil


investigation


a seismic


test


which


places


both


the


source


and


receivers


on the


ground


surface.


Two


receivers

a vertical


placed

impact


at varying


load


spacings


measure


use


surface


waves

wave


generated

properties


between


receivers.


An inversion


program


is used


estimate


the


shear


wave


velocity


and


shear


modulus


profiles.


These


profiles


can


used


the


combat


controller


compare


results


at different


stations


down


the


unsurfaced


airfield.












the


wave


is dependent


wavelength


frequency)


the


wave.


The


variation


of velocity


with


frequency


called


dispersion


occurs


because


waves


of different


wavelengths


sample


different


layer


depths.


Low


frequency


waves

deeper


propagate

layers.


with

High


longer

frequent


wavelengths

cv waves nr


-A


and


opaga


therefore

te with


sample


shorter


wavelengths


the


near


surface


layers.


the


wavelength


increases,


particle


motion


found


deeper


layers,


shown


Figure


.22.


The


velocity


the


wave


influenced by t

particle motion


properties


occurred.


the


In Figure


layer


.22(c),


which the

the properties


the


surface


layer,


the


base


and


some


the


subgrade


effect


velocity


that


wave.


In Figure


.22(b),


particle


therefore


layer.


motion


the


This


limited


velocity

technique


to the


surface


wave


allows


surface


only

waves


layer


and


effected


to sample


that

the


different


layers


wavelengths).


The


creating

surface w


a wide


ave


range


velocity


frequencies


then


compared


with


corresponding


dispersion


curve


wavelength


(discussed


and


later)


plotted


Using


on a


an inversion


process,


shear


wave


velocity


the


different


layers


can


be calculated.


C











































. Surface Layer .

S.**** ..**********. .****
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F:"'"' Base "'"'""-*:
* S S S S S S S

V It 1 I I 1


: ',:: Subgracle :,

g / # d # # # # d # /


em a
we
- -


I -


Particle
Motion

m n a


a n- ---


Depth


Particle
Motion


Depth


a. Material Profile


b. Shorter Wavelength. ).


c. Longer Wavelength. &2












SASW


Field


Testing


Ecruiment


The


field


SASW


equipment


consists


an impact


source,


seismic


receivers,


a recording


devide


as shown


Figure


The


impact


source


generally


some


type


of drop


hammer


. At close


receiver


spacings


feet)


hand-held


hammers


are


used


while


eater


spacings


to 16 feet)


sledge-hammers


are


generally


used


Stokoe


et al. (1988)


have


investigated


using


to 2000


Ib dropped


weights


with


good


success


and


have


suggested


using


bulldozers


and


dynamic


compaction


weights


create


the


very


frequencies


required


depths


of 500


feet.


However


, the


larger


weights


are


quite


destructive


and


could


be prohibitive


some

high


sites. A p

frequencies


iezoelectric


the


shaker


to 50 kHz


can

rang


be used

e for e


to generate


valuation


near


surface


layers.


Once


monitor


the


the


source


surface


has

wave.


impacted

The fr


two


vertical


equenci


receivers


the


wave


influence


the


type


of receiver


used.


Vertical


velocity


receivers


well


with


at soil


natural


sites


frequencies


to 500


.5 Hz perform


piezoelectric


accelerometers


do well


at pavement


sites


where


frequency


range


from


50kHz


(Stokoe


et al. 1988)


SASW


testing


usually


done


with


receivers


at different


spacings


using


one


v


w


























Microcomputer


Piezoelectric
Noise Source


Vertical


Accelerometer


Waveform
Analyzer


Vertical


Accelerometer


D(variable)


--


00000
00000











feet.


These


spacings


can


be used


to evaluate


depths


of 60 feet.


The


recording


devise


usually


some


kind


of dynamic


signal


analyzer


with


a micro-computer.


The


digital


signal


analyzer


a digital


oscilliscope


that


has


the


ability


perform


calculations


either


time


or frequency


domains.


Figure


shows


some


typical


field


data


one


receiver


spacing.


The


phase


the


cross


power


spectrum


plots


the


phase


difference


between


receivers


as a function


of frequency.


dispersion


measure


signals


The


curve

the q


recorded.


phase


discussed


quality


difference


later.


(signal


A ratio


used


The


to noise


one


to generate


coherence


ratio)


signifies


a high


the


is a

the


quality


signal


while


a ratio


zero


indicates


poor


quality.


.4.4 Dispersion


Calculations


The

each


dynamic

receiver


digital

spacing


analyzer


and


collects


transforms


the


them


time


into


records


records


the


frequency


domain


using


a fast


fourier


transform


algorithm.


Inside


the


frequency


domain


, the


phase


difference


between


two


receivers


plotted


against


frequency.


The


time


delay


from


one


receiver


the


other


a function


of frequency


and

































CROSS,
ISO


Phase


DecQ


- iao


FPxd


S


SPEC


Y 0


COHE
1.0

Mag


0
Pxd


o 0
Y 0


Unit


Hz 1S


---- -- uIII I-ii -i I --- ~ ^


OXOv l


SAv












= frequency


(Hertz)


surface


V,(f)


wave


velocity


= D/t(f)


.33)


where


= distance


between


receivers


The


wavelength


surface


wave,


- Vs/f


.34)


These


calculations


preformed


Equations


a micro-computer


.33,


each


and


frequency


are


and


the


result


plotted


as a dispersion


curve.


Each


dispersion


curve

form


generated


one


from


integrated


specific

dispersion


receive

curve


spacings


as shown


merged


Figure


.25.


Inversion


Process


The


purpose


the


inversion


process


is to back


calculate


shear


velocity


moduli


differing


soil


layers.


The


process


used


today


is an iterative


procedure


that


matches


theoretical


dispersion


curve


with


the


experimental


dispersion


curve


obtained


the


field.


Each


iteration


assumes


a shear


wave


velocity


thickness


layer


and


modifies


experimental


accordingly


and


to obtain


theoretical


similarity


curves.


between


Figure


w w w


w w m






































120



150



180


200 400 600
Shear Wave Velocity


800


1000


ftsec


__












been


measured


(Roesset


et al. 1991)


= CV.


G(B)
E(


(7/g) (Vs)


2 (


= 2G(l+u)


.35)
.36)
.37)


where


= 1.135


- 0.182


v (for


= shear


modulus


= total


unit


weight


= acceleration


due


to gravity


= Young


= poisson


s modulus


s ratio


Since


measurements


are


seismically


made


with


strains


below


.001


percent,


equations


.37,


represent


maximum


moduli


values.


Qualitative


SASW


Estimation


Density


Usina


the


Method


One


by-products


of obtaining


the


shear


wave


velocity


a site


is that


situ


densities


can


inferred


Stokoe


et al.


(1988)


demonstrate


that


thi


can


done


sands


and


gravels


comparing


measured


shear


wave


velociti


with


values


calculated


using


an empirical


relationship


developed


Seed


et al. (1986)


A small


strain


value


of shear


modulus,


G.m,


given












= mean


effective


principle


stress.


Shear


modulus


shear


velocity


are


related


Equation


(7/g)v,2 (


.39)


where


= total


unit


weight


= gravitational


acce


leration


Stokoe


et al.


(1988)


demonstrate


that


equations


and


are


combined,


the


shear


wave


velocity


can


be expressed


[(1000)(g/7)(K,2)]0


.40)


Using


Equation


2.40


the


variation


of shear


velocity


with


depth


and


density


can


be evaluated


at a site


Using


a qualitative


approach,


Stokoe


et al. (1988)


suggest


assuming


diff


erent


values


of K2


which


reflect


various


densiti


es.


example,


values


such


as 30,


and


represent


loose


, medium


dense


and


very


dense


sands


while


values


of 40,


and


might


used


gravel


addition,


' must


be calculated


each


depth


using


the


expression











= coefficient


of earth


pressure


at rest


However,


Stokoe


et al.


(1988)


caution


that


using


Equation


there


are


at least


five


assumptions


implicitly


made:


level


ground


principal


stresses


are


oriented


the


vertical


and


horizontal


directions


intermediate


and


minor


principal


stresses


are


equal


of deposit


little


can


be neglected


or no cementation


exists


Stokoe


et al.


(1988)


demonstrated


this


technique


using


three


sites


that


were


hard


to sample


with


traditional


methods.


Figure


.27 present


results


from


the


sites


terms


of shear


velocity


, depth,


and


density.


Figure


2.27(a)


shows


very


loose

Figure


layer


between


.27(b)


shows


10 and


a loose


feet

layer


the


between


Spirit


and


Lake


area,


16 feet


Figure


demonstrates


the


effects


of compactions


efforts


at Jackson


Lake


Dam,


Wyoming.


Determininac


Surface


Laver


Values


Thickness


and


Modulus


The


goal


of SASW


testing


to determine


the


stiffness


of layers


using


dispersive


properties


of surface
































a. Debris Blockages Mount SL Helens


b. Gravelly Marial ner Boah
Peak. Idaho


Shear Wave Velocity (ft/sec)


c. Sils and Sily Sands a Jackson Lake Dam. Wyoing

























U

QC
'I

Ic
*0


10-1 100 10


Wavelength, LR











wave


propagation


a uniform


half-space.


this


figure,


surface


wave


phase


velocity


independent


the


wavelength


because


the


section


has


uniform


stiffness.


Figure


.29 shows


a dispersion


curve


Rayleigh


waves


propagating


a soft


over


stiffer


half


-space.


Noti


that


at short


wavelengths,


surface


wave


phase


velocity


equal


to the


value


the


surface


layer


wavelength


increases,


however


, the


surface


velocity


effected


stiffer


material


below


and


averaging


the


two


layers


results


a higher


surface


wave


phase


velocity


Figure


shows


a stiff


over


soft


half-space


since


the


short


wavelengths


(high


frequency


have


a higher


surface


wave


phase


velocity


than


the


long


wavelengths


(low


frequencies


Thi


would


simulate


a base


course


over


a subgrade.


Roesset


et al.


(1990)


suggests


that


since


short-wavelengths


sample


only


the


stiffness


top


layer,


then


the


shear


wave


velocity,


shear


modulus,


Young


s modulus


top


layer


may


be calculated


using


Equations


, 2.36,


.37.


In addition,


Roesset


et al.


(1990)


point


out


that


using


the


critical


wavelength


shown


Figure


.31,


the


thickness


top


layer


may


estimated.


Roessett


(1990)


reported


on the


two


pavement


sections


shown


Figures 2.


and


Figure 2.


shows


a section


with





































10-' 100 101


Wavelength, LR





































10-' 100 10'


Wavelength,































Wavelength,


(Log scale)



















6000


5000


4000





3000





2000


S1 1


Wavelength



















6000




5000




4000





3000





2000


Wavelength











high


because


moduli


measured


at strain


levels


associated


with


seismi


testing


are


maximum


values.


shown


Figure

inches


a prediction


as compared


cores


top


of 6.96


layer thickness

inches, which


6.12


compares


reasonably


well.


Figure


shows


similar


data


with


Young


s modulus


value


of 2


x 10lOsf


and


estimated


surface


layer


thickness


5.04


inches


. The


cored


thickness


was


5.04


inches


and


compares


very


favorably.


It has


been


the


intent


chapter


to provide


reader


with


the


necessary


background


to logically


follow


and


understand


the


research


esented


the


following


chapters.


chapter


has


discussed


basi


airfield


trafficability


concepts,


seismic


U.S.A.F


surveying


. unsurfaced


using


airfield


spectral


evaluation


analysis


techniques


of surface


waves.


Chapter


will


present


the


design


and


development


the


Automated


Airfield


Dynamic


Cone


Penetrometer


(AADCP)