Determining the Strain Rate of Controlled-Strain Loading Consolidation Test with hydraulic conductivity

This note presents a rational procedure to determine the initial strain rate of controlled-strain loading (CSL) consolidation test and control the strain rate during the test within the permissible limits of pore pressure ratio. The initial strain rate is determined by measuring the hydraulic conductivity of soil specimen by conducting a rapid falling head hydraulic conductivity test using a standpipe of 3 mm diameter. The strain rate is controlled during the test by restricting the maximum allowable pore pressure ratio at the base of specimen close to 15%. The testing procedure is validated by performing a series of experiments on reconstituted and undisturbed soil samples. The results from the proposed method are compared with those obtained from the Incremental Loading (IL) consolidation test. The test results prove that the proposed method can be conveniently used to perform the CSL consolidation tests for the determination of the consolidation properties of soils.