Estimation of Soil Permeability Using An Acoustic Technique Department of Civil Engineering The University of Mississippi University University, MS Kim, Jin Won And 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. Olemiss Civil Engineering

 Maximum frictional loss between solid particles and water occurs when motions of solid particles and water are pushed longer by a certain frequency Background

Receiver 1 Receiver 2 Difference of amplitude means attenuation Difference of amplitude means attenuation X 2X 2 X 1X 1 Olemiss Civil Engineering

attenuation frequency fc f c : Characteristic Frequency = frequency at Maximum Damping Characteristic frequency is related to the viscosity of the fluid and permeability of soils. Olemiss Civil Engineering

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 Olemiss Civil Engineering

Biot Equation (1956) Velocity (m/s) Frequency (Hz) Characteristic frequency Olemiss Civil Engineering

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. Olemiss Civil Engineering

Experimental set up Underground Actuator Digital oscilloscope Wave Generator Amplifier Receiver 1 Receiver 2 Olemiss Civil Engineering

. Lab. Testing

Sample Close Up Underground Actuator Receiver 2 Receiver 1 Acoustic Absorber Olemiss Civil Engineering

Field Testing Olemiss Civil Engineering

Measured Signals Receiver 1 Receiver 2 Olemiss Civil Engineering x1x1 x2x2 Frequency : 400 Hz Amplitude : x 1 ≈ x 2

Olemiss Civil Engineering Receiver 1 Receiver 2 x1x1 x2x2 Frequency : 900 Hz Amplitude : x 1 ≈ x 2 Receiver 2 Receiver 1

Olemiss Civil Engineering x1x1 x2x2 Frequency : 3000 Hz Amplitude : x 1 < x 2 Receiver 2 Receiver 1

Attenuation coefficient = attenuation coefficient Underwater actuator Amp.:A 1 Amp.: A 2 r1r1 r2r2 Olemiss Civil Engineering

Field Test at the Sardis Lake and Wellsgate Lake Characteristic frequency is 3000 Hz Olemiss Civil Engineering Attenuation coefficient Frequency (Hz) Attenuation coefficient Sardis Wellsgate

Field Test at the Highway 7 and Yalobusha River Characteristic frequency is 4400 Hz Olemiss Civil Engineering Frequency (Hz) Attenuation coefficient

Checking system compliancy Lab. test results of saturated soil and dry soil Attenuation coefficient Frequency (Hz) Saturated condition : W = 100 (%) Dry condition : W = (%) Olemiss Civil Engineering

Checking system compliancy Lab. test with water only System characteristic frequency is Hz Frequency (Hz) Olemiss Civil Engineering 0.47 m 0.92 m Errors from incorrect alignment Errors from reflection

Attenuation coefficient Frequency (Hz) Ratio A2/A1 System characteristic frequency is Hz Olemiss Civil Engineering

General properties of soil  General properties of soil (%) (t/m 2 ) (%)(t/m 2 ) Properties of Sardis Lake soilProperties of Yalobusha River soil Olemiss Civil Engineering SandSiltGravel SandSiltClay

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 Value of Soil Permeability from lab is smaller than expected value Olemiss Civil Engineering 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. Olemiss Civil Engineering

Thank you for your attention Questions? Olemiss Civil Engineering