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

OverviewHydraulic Conductivity and Piezocone Hydraulic Conductivity by Piezocone Penetration TestPrevious workCurrent resultsConclusions

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.

PiezoconeUsed forSite explorationAssessment of ground improvementEvaluation of contaminant transport

MeasuresFrictional resistancePore PressureEnd bearing

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).

Pore pressure response for soil element during PCPTChung R. Song and George Z. Voyiadjis (2003)

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

Relations between the dimensionless excess PWP during Piezocone Penetration and dimensionless Hydraulic ConductivityChung R. Song and George Z. Voyiadjis (2003)

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

Finite Element MeshChung R. Song and George Z. Voyiadjis (2003)

Coupled equations

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.

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.

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

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

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

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

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

THANK YOU