Sensitivity Analysis of the Hydraulic Conductivity of Compacted Lateritic Soil and Bentonite Composite

摘要

This study investigates the sensitivity of variables that affect hydraulic conductivity of compacted lateritic soil - bentonite mixtures for use as waste landfill liner. Reliability indices for mixtures containing up to 10% bentonite were computed from a predictive model incorporated into a FORTRAN-based first-order reliability program (FORM). The model relates hydraulic conductivity (k) to plasticity index (PI), initial saturation (S_i), clay content (C) and compaction effort (E), considering k as a lognormally distributed function. Lateritic soil - bentonite mixtures used in generating k data were compacted with standard Proctor (SP), West African Standard (WAS) or 'intermediate' and modified Proctor (MP) energies. The reliability indices obtained showed that performance level was high (4.16 to 5.71), establishing a decreasing trend as the coefficients of variation changed from 10% - 100% for lognormal k relationship as well as for PI, S_i and C over the range of compactive efforts used in the study. These results can guide designers in identifying and screening variables that yield acceptable k for soil - bentonite liner materials and the selection of compaction procedures that will provide the best condition for the construction of high integrity liner systems.