Slug Test Analysis in Vertical Cutoff Walls with Consideration of Filter Cake

In constructing a vertical cutoff wall, bentonite-water slurry is frequently used to maintain the stability of sidewalls during excavation before backfilling the trench with less permeable materials to complete the cutoff wall construction. This procedure leads to a thin but relatively impermeable layer, called a filter cake, on the excavation surface. The aim of this paper is to examine the effect of a filter cake on evaluating hydraulic conductivity of the cutoff wall backfill through a slug test analysis with the aid of the verified numerical program, Slug_3D. As an upper bound solution for evaluation of the hydraulic conductivity of the cutoff wall backfill, no-flux boundary conditions for the boundaries of cutoff walls are imposed to consider the effect of filter cakes. The type-curve method and modified line-fitting method are employed to reanalyze the case of EMCON/OWT, Inc., as an example. The previous analysis, without consideration of a filter cake, is compared with the current results that cons...

[1]  Hangseok Choi.  Numerical Model for Analyzing Slug Tests in Vertical Cutoff Walls , 2007 .

[2]  Haeng Woo Lee,et al.  Correlation between the laboratory and in-situ permeabilities for the embankments , 2007 .

[3]  George M. Filz,et al.  Closure of "Measuring the Hydraulic Conductivity of Soil –Bentonite Backfill" , 2004 .

[4]  HangSeok Choi.  Analysis of Slug Tests to Determine Hydraulic Conductivity of Vertical Cutoff Walls , 2002 .

[5]  D. E. Daniel,et al.  Slug test analysis in vertical cutoff walls. I: Analysis methods , 2006 .

[6]  J. D. Bredehoeft,et al.  Response of a finite-diameter well to an instantaneous charge of water. Paper No. H-21 , 1966 .

[7]  M. J. Hvorslev.  Time lag and soil permeability in ground-water observations , 1951 .

[8]  James L. Sherard,et al.  Filters for Silts and Clays , 1984 .

[9]  Jr . James J. Butler,et al.  Slug tests in site characterization; some practical considerations , 1996 .

[10]  James L. Sherard,et al.  Basic Properties of Sand and Gravel Filters , 1984 .

[11]  K. Bradbury,et al.  Hydraulic Conductivity Determinations in Unlithified Glacial and Fluvial Materials , 1990 .

[12]  D. E. Daniel,et al.  Slug Test Analysis in Vertical Cutoff Walls. II: Applications , 2006 .

[13]  Gary R. Chirlin,et al.  A Critique of the Hvorslev Method for Slug Test Analysis: The Fully Penetrating Well , 1989 .

[14]  Jeremy Paul Britton.  Soil-Bentonite Cutoff Walls: Hydraulic Conductivity and Contaminant Transport , 2001 .

[15]  Beverly L. Herzog,et al.  Hydraulic Conductivity At a Hazardous Waste Disposal Site: Comparison of Laboratory and Field-Determined Values , 1986 .

[16]  H. Bouwer,et al.  A slug test for determining hydraulic conductivity of unconfined aquifers with completely or partially penetrating wells , 1976 .

[17]  Gilbert R. Tallard,et al.  Slurry Trenches for Containing Hazardous Wastes , 1984 .

[18]  D. J. Dappolonia.  Soil-Bentonite Slurry Trench Cutoffs , 1980 .

[19]  Ma Khoury,et al.  Design, Construction and Performance of a Soil-Bentonite Cutoff Wall Constructed in Two Stages , 1992 .

[20]  J. J. Butler,et al.  The Design, Performance, and Analysis of Slug Tests , 1997 .

[21]  H. Bouwer.  The Bouwer and Rice Slug Test — An Updatea , 1989 .

[22]  Kevin L. Nash,et al.  Stability of Trenches Filled with Fluids , 1974 .

[23]  Hangseok Choi,et al.  Hydraulic conductivity evaluation of vertical barrier walls , 1999 .

[24]  Hangseok Choi,et al.  Slug Test Analysis to Evaluate Permeability of Compressible Materials , 2008, Ground water.

[25]  Hangseok Choi,et al.  Hydraulic Conductivity Evaluation of Vertical Cutoff Walls Bearing Filter Cake From Slug Test Analysis , 2010 .

[26]  George M. Filz,et al.  DETERMINING HYDRAULIC CONDUCTIVITY OF SOIL-BENTONITE USING THE API FILTER PRESS , 2001 .

[27]  Samuel P. Clemence,et al.  In-Place Permeability Measurement of Slurry Trench Cutoff Walls , 1986 .

[28]  D. E. Daniel,et al.  Modified Fluid Loss Test as an Improved Measure of Hydraulic Conductivity for Bentonite , 2008 .

[29]  James J. Butler,et al.  Slug tests in partially penetrating wells , 1994 .

[30]  J. Evans,et al.  The State-of-Stress in Soil-Bentonite Slurry Trench Cutoff Walls , 1995 .

[31]  John D. Bredehoeft,et al.  On the analysis of ‘slug test’ data , 1973 .

[32]  George M. Filz,et al.  Formation and Properties of Bentonite Filter Cakes , 1998 .

[33]  Roger Thunvik,et al.  Determination of formation permeability by double-packer tests , 1984 .