Influence of Leaching on Volume Change of a Gypseous Soil

As part of a research program the influence of leaching on volume change of gypseous soil was examined by a laboratory testing program on relatively undisturbed soil samples from a site in northern Iraq. One dimensional compression tests coupled with continuous flushing on the investigated soil were conducted in Rowe cells. Conventional consolidation tests and interpretation procedures are not applicable to the gypseous soil investigated. These tests and interpretations do not account for solution and flushing of gypsum due to leaching. Analyses of test results led to derivation of a phenomenological expression that characterizes stress-strain-time relations during leaching of the gypseous soil. The time to reach a specified vertical leaching strain may be calculated for different stress levels with relative ease.