estimation of soil permeability using an acoustic technique department of civil engineering the...

Estimation of Soil Permeability Using An Acoustic Technique

Department of Civil Engineering The University of Mississippi University

University, MS 38677

Kim, Jin WonAnd

Chung R. Song

Introduction Background Experiments Results Conclusions

• Contents

Olemiss Civil Engineering

• Introduction

The estimation of permeability of soils using acoustic techniques is proposed here.

The propagation of elastic waves in saturated soils are the

coupled action between solid particles and pore water.

The coupled behavior involves the permeability of soils.

By analyzing the propagation of elastic waves in saturated

soils, the permeability of soils is estimated.


Maximum frictional loss between solid particles and water occurswhen motions of solid particles and water are pushed longer by a certain

frequency

• Background

Receiver 1

Receiver 2

• Difference of amplitude means attenuationDifference of amplitude means attenuation

X 2

X 1


att

en

ua

tio

n

frequencyfc

fc : Characteristic Frequency= frequency at Maximum Damping

Characteristic frequency is related to the viscosity of the fluid and permeability of soils.


• Historic development

Morse (1952)

Biot (1956, 1962)

Attenborough (1982, 1983)

Stoll (1980) Yamamoto(2002)

Detournay and Cheng (1994)

Sabatier et al. (1990, 1996)

Yamamoto (2002) for rocks containing hydrocarbon


Biot Equation (1956)

2 2

11 22 1221 2 1 2 1 22

12 22

12 2

2 11 22 122

12 22

12

2

2

c c

c c

V f

V f

V f

V f

Velocity (m/s)

Frequency (Hz)Characteristic frequency


2211 22 12

1 21 12 22

1

2c

c

L f

x f

12 2

11 22 12

2 12 22

1

2c

c

L f

x f


attenuation

Frequency (Hz)Characteristic

frequency

Biot Equation

In the equation, g is the gravity, f is the frequency in hertz, and k is the permeability in m/sec unit.

k

gf c

2


• Experimental set up

Underground Actuator

Digital oscilloscope

Wave Generator

Amplifier

Receiver 1

Receiver 2



. Lab. Testing

• Sample Close Up

Underground Actuator

Receiver 2

Receiver 1

Acoustic Absorber


• Field Testing


•Measured Signals

Receiver 1

Receiver 2


x1

x2

Frequency : 400 Hz Amplitude : x1 ≈ x2


Receiver 1

Receiver 2

x1

x2

Frequency : 900 Hz Amplitude : x1 ≈ x2

Receiver 2

Receiver 1


x1

x2

Frequency : 3000 Hz Amplitude : x1 < x2

Receiver 2

Receiver 1

• Attenuation coefficient

2 1( )2 1

r rA Ae

= attenuation coefficient

Underwater actuator

Amp.:A1Amp.: A2

r1r2


• Field Test at the Sardis Lake and Wellsgate Lake

Characteristic frequency is 3000 HzOlemiss Civil Engineering

Attenuation coefficient

Frequency (Hz)

-3

-2

-1

0

1

2

3

4

5

6

0 1000 2000 3000 4000 5000 6000

-2

-1

0

1

2

3

4

0 1000 2000 3000 4000 5000

Frequency (Hz)


Sardis

Wellsgate

• Field Test at the Highway 7 and Yalobusha River

Characteristic frequency is 4400 Hz


Frequency (Hz)


-3

-2

-1

0

1

2

3

4

5

6

0 2000 4000 6000 8000 10000 12000

• Checking system compliancy Lab. test results of saturated soil and dry soil

-6

-4

-2

0

2

4

6

8

0 500 1000 1500 2000 2500 3000 3500 4000 4500

saturated soil dry soil


Frequency (Hz)

Saturated condition : W = 100 (%) Dry condition : W = 0.098 (%)


•Checking system compliancy Lab. test with water only

System characteristic frequency is 10000 Hz

Frequency (Hz)


0.47 m

0.92 m

0

1

2

3

4

5

0 2000 4000 6000 8000 10000 12000 14000

frequency (Hz)

0

1

2

3

4

5

0 2000 4000 6000 8000 10000 12000 14000

frequency (Hz)

Errors from incorrect alignment

Errors from reflection

0

1

2

3

4

5

0 2000 4000 6000 8000 10000 12000 14000

-1

0

1

2

3

4

5

0 2000 4000 6000 8000 10000 12000 14000


Frequency (Hz)

Frequency (Hz)

Ratio A2/A1

System characteristic frequency is 10000 HzOlemiss Civil Engineering

• General properties of soil

General properties of soil

nPercent finer versus Grain Size

0

20

40

60

80

100

0.010.1110

Grain size, D(mm)

Perc

ent f

iner

(%)

(t/m2)

2.65 24.15 1.161 0.640 0.390

(%) (t/m2)

2.67 35.90 1.364 0.958 0.489

Percent versus Grain Size

0

20

40

60

80

100

0.0000.0010.0100.1001.00010.000

Grain Size, D(mm)

Perce

nt Fi

ner

Properties of Sardis Lake soil Properties of Yalobusha River soil


Gsw d e n Gs

nnnnn

e nw d

Sand SiltGravel Gravel Sand Silt Clay

• Comparison of results with conventional permeability data

　Average soil permeability　(from constant head test)　

Estimated soil permeability　(from Biot equation)　

　

　　　

　　　　　

Sardis Lake 2.97×10-5 m/sec 2.03×10-4 m/sec　

Yabolusha river

4.35×10-6 m/sec　

1.73×10-4 m/sec　

Q lk

A h T

• Value of Soil Permeability from lab is smaller than expected value


2 c

gk

f

• Constant head permeability tests were carried out for Sardis Lake sands and

Yalobusha River soils

Conclusions

Theoretically sound.

Experimentally complicated but possible.

Acoustic technique is an easy way to estimate the permeability of soils.

This technique is a non-destructive method.

Application of the proposed method may be feasible for other types of soils. – under the research in Olemiss Civil Eng. Dept.


Thank you for your attention

Questions?


estimation of soil permeability using an acoustic technique department of civil engineering the...

Documents

permeability of soils

receiver 2x1x2receiver

saturated soils

receiver 1x1x2receiver

sardis lake

test result

a2r1r2 field test

pore water