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An Easy Method of Determining Hydraulic Conductivity of Soils using Pore Pressure Response of Piezocone Penetration TestChung R Song, Ph.D., University of MississippiSreekar Pulijala, Graduate Assistant, University of Mississippi
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OverviewHydraulic Conductivity and Piezocone Hydraulic Conductivity by Piezocone Penetration TestPrevious workCurrent resultsConclusions
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Hydraulic ConductivityDescribes the rate at which water can move through a permeable medium.
Why do we need to know hydraulic conductivity of the soil ??
However, the determination of hydraulic conductivity is time consuming and not easy.
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PiezoconeUsed forSite explorationAssessment of ground improvementEvaluation of contaminant transport
MeasuresFrictional resistancePore PressureEnd bearing
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Hydraulic Conductivity by Piezocone Penetration Test (PCPT)Advance Piezocone to the desired depth and hold it for dissipation test.
Reliable values of Hydraulic Conductivity, compared to other field tests.
This is still time consuming and expensive (half day).
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Pore pressure response for soil element during PCPTChung R. Song and George Z. Voyiadjis (2003)
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New Method To overcome the drawbacks of conventional dissipation test and provide a more realistic theoretical background.
Key idea : Pore Pressure response of saturated soils is not only a function of stress-strain parameters but also of hydraulic conductivity. Song.C.R and Voyiadjis.G.Z (2003) Pore pressure observed by clayey soils and sandy soils.Clay : High PWPSand : Low or Zero PWP
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Relations between the dimensionless excess PWP during Piezocone Penetration and dimensionless Hydraulic ConductivityChung R. Song and George Z. Voyiadjis (2003)
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Previous workCorrelates the magnitude of pore water pressure to the Hydraulic Conductivity directly.
Potential for real time process.
An axi- symmetric FE program that is capable of simulating behavior of soils with the advancement of the Piezocone tip was developed and used.
Uses the coupled theory of mixtures
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Finite Element MeshChung R. Song and George Z. Voyiadjis (2003)
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Coupled equations
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Objective
Use of Song and Voyiadjis (2003)s method (i.e. New method)
To perform numerical analyses for various soil conditions and provide simple design charts (monogram type) that an engineer can use without great difficulties.
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Current stageSetting up penetration depth and number of increments
By changing some material properties like, Permeability, M
Corresponding values of PWP are obtained for each varying properties when others are kept constant.
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Permeability (k) vs. PWP
PERMEABILITY vs PWP
553.101
552.872
550.653
532.215
467.414
228.846
35.585
3.979
k
PWP
PERMEABILITY(k) vs PWP
LOG PERMEABILITY vs PWP (2)
553.101
552.872
550.653
532.215
467.414
228.846
35.585
3.979
k
PWP
kappa=.02,lambda=0.17,M=1.2
VARYING k
553.101567.481
552.872566.98
550.653561.022
532.215518.921
467.414425.82
228.846169.838
35.58520.74
3.9792.228
600
200
300
400
500
100
k (m/sec)
PWP (KPa)
Sheet1
5.00E-11553.101567.481
5.00E-10552.872566.98
5.00E-09550.653561.022
5.00E-08532.215518.921
5.00E-07467.414425.82
5.00E-06228.846169.838
5.00E-0535.58520.74
5.00E-043.9792.228
Sheet2
Sheet3
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M vs. PWP
LOG k vs PWP
567.481
566.98
561.022
518.921
425.82
169.838
20.74
2.228
k
PWP
kappa=.005,lambda=.13,M=1.0
LOG Lambda vs PWP
499.152
471.47
446.441
424.979
399.647
361.256
LAMBDA
PWP
LAMBDA Vs PWPM=1.2,K=0.04,k=0.5E-09
k vs PWP
567.481
566.98
561.022
518.921
425.82
169.838
20.74
2.228
k
PWP
Permeability(k) Vs PWPkappa=0.005,lambda=0.13,M=1.0
M vs PWP(1)
343.104
389.155
428.257
471.138
510.971
552.872
M
PWP
kappa=.02,lambda=0.17,k=0.5E-09
M vs PWP(2)
280.852
310.178
338.452
366.629
395.412
424.979
M
PWP
M vs PWPkappa=.04,lambda=0.32,k=0.5E-09
LAMBDA vs PWP(1)
499.152
471.47
446.441
424.979
399.647
361.256
LAMBDA
PWP
kappa=.04,M=1.2,k=0.5E-09
kappa vs pwp
587.905
513.414
471.445
445.463
434.713
424.695
kappa
PWP
lambda=.24,M=1.2,k=0.5E-09
varying M
343.1040.7280.852
389.1550.8310.178
428.2570.9338.452
471.1381366.629
510.9711.1395.412
552.8721.2424.979
M
PWP( KPa)
VARYING LAMBDA
499.152477.99
471.47468.24
446.441460.039
424.979454.116
399.647448.862
361.256414.142
Lambda
PWP
Sheet1
LPWP
0.2499.152477.99
0.24471.47468.24
0.28446.441460.039
0.32424.979454.116
0.36399.647448.862
0.4361.256414.142kappaPWP
0.005587.905
0.02513.414
0.04471.445
0.06445.463
0.07434.713
0.08424.695
kPWPMPWPMPWP
5.00E-11567.4810.7343.1040.7280.852
0.0000000005566.980.8389.1550.8310.178
0.000000005561.0220.9428.2570.9338.452
0.00000005518.9211471.1381366.629
0.0000005425.821.1510.9711.1395.412
0.000005169.8381.2552.8721.2424.979
0.0000520.74
0.00052.228
Sheet2
log kappa vs pwp (2)
587.905
513.414
471.445
445.463
434.713
424.695
kappa
PWP kpa
Sheet3
MBD0145279D.unknown
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vs. PWP
LOG k vs PWP
567.481
566.98
561.022
518.921
425.82
169.838
20.74
2.228
k
PWP
kappa=.005,lambda=.13,M=1.0
LOG Lambda vs PWP
499.152
471.47
446.441
424.979
399.647
361.256
LAMBDA
PWP
LAMBDA Vs PWPM=1.2,K=0.04,k=0.5E-09
k vs PWP
567.481
566.98
561.022
518.921
425.82
169.838
20.74
2.228
k
PWP
Permeability(k) Vs PWPkappa=0.005,lambda=0.13,M=1.0
M vs PWP(1)
343.104
389.155
428.257
471.138
510.971
552.872
M
PWP
kappa=.02,lambda=0.17,k=0.5E-09
M vs PWP(2)
280.852
310.178
338.452
366.629
395.412
424.979
M
PWP
M vs PWPkappa=.04,lambda=0.32,k=0.5E-09
LAMBDA vs PWP(1)
499.152
471.47
446.441
424.979
399.647
361.256
LAMBDA
PWP
kappa=.04,M=1.2,k=0.5E-09
kappa vs pwp
587.905
513.414
471.445
445.463
434.713
424.695
kappa
PWP
lambda=.24,M=1.2,k=0.5E-09
varying M
343.1040.7280.852
389.1550.8310.178
428.2570.9338.452
471.1381366.629
510.9711.1395.412
552.8721.2424.979
M
PWP
VARYING LAMBDA
499.152477.99
471.47468.24
446.441460.039
424.979454.116
399.647448.862
361.256414.142
Lambda
PWP
Sheet1
LPWP
0.2499.152477.99
0.24471.47468.24
0.28446.441460.039
0.32424.979454.116
0.36399.647448.862
0.4361.256414.142kappaPWP
0.005587.905
0.02513.414
0.04471.445
0.06445.463
0.07434.713
0.08424.695
kPWPMPWPMPWP
5.00E-11567.4810.7343.1040.7280.852
0.0000000005566.980.8389.1550.8310.178
0.000000005561.0220.9428.2570.9338.452
0.00000005518.9211471.1381366.629
0.0000005425.821.1510.9711.1395.412
0.000005169.8381.2552.8721.2424.979
0.0000520.74
0.00052.228
Sheet2
log kappa vs pwp (2)
587.905
513.414
471.445
445.463
434.713
424.695
kappa
PWP (KPa)
Sheet3
MBD0145279D.unknown
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vs. PWP
LOG k vs PWP
567.481
566.98
561.022
518.921
425.82
169.838
20.74
2.228
k
PWP
kappa=.005,lambda=.13,M=1.0
LOG Lambda vs PWP
499.152
471.47
446.441
424.979
399.647
361.256
LAMBDA
PWP
LAMBDA Vs PWPM=1.2,K=0.04,k=0.5E-09
k vs PWP
567.481
566.98
561.022
518.921
425.82
169.838
20.74
2.228
k
PWP
Permeability(k) Vs PWPkappa=0.005,lambda=0.13,M=1.0
M vs PWP(1)
343.104
389.155
428.257
471.138
510.971
552.872
M
PWP
kappa=.02,lambda=0.17,k=0.5E-09
M vs PWP(2)
280.852
310.178
338.452
366.629
395.412
424.979
M
PWP
M vs PWPkappa=.04,lambda=0.32,k=0.5E-09
LAMBDA vs PWP(1)
499.152
471.47
446.441
424.979
399.647
361.256
LAMBDA
PWP
kappa=.04,M=1.2,k=0.5E-09
kappa vs pwp
587.905
513.414
471.445
445.463
434.713
424.695
kappa
PWP
lambda=.24,M=1.2,k=0.5E-09
varying M
343.1040.7280.852
389.1550.8310.178
428.2570.9338.452
471.1381366.629
510.9711.1395.412
552.8721.2424.979
M
PWP
VARYING LAMBDA
499.152477.99
471.47468.24
446.441460.039
424.979454.116
399.647448.862
361.256414.142
Lambda
PWP (KPa)
Sheet1
LPWP
0.2499.152477.99
0.24471.47468.24
0.28446.441460.039
0.32424.979454.116
0.36399.647448.862
0.4361.256414.142kappaPWP
0.005587.905
0.02513.414
0.04471.445
0.06445.463
0.07434.713
0.08424.695
kPWPMPWPMPWP
5.00E-11567.4810.7343.1040.7280.852
0.0000000005566.980.8389.1550.8310.178
0.000000005561.0220.9428.2570.9338.452
0.00000005518.9211471.1381366.629
0.0000005425.821.1510.9711.1395.412
0.000005169.8381.2552.8721.2424.979
0.0000520.74
0.00052.228
Sheet2
log kappa vs pwp (2)
587.905
513.414
471.445
445.463
434.713
424.695
kappa
PWP
Sheet3
MBD0145279D.unknown
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ConclusionsThe trend of PWP observed by the change of different parameters is reasonable.
Easy to use design charts : a handy tool to geotechnical engineers for the determination of hydraulic conductivity
Reduction in the computation time
Can be used in seepage analysis, soil classification, detection of underground aquifers, etc
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THANK YOU