Volume change correction and soil-water characteristics of remodeling expansive soil under dehydration path

A set of dehydration tests and shrinkage tests of the specimens with five different initial dry densities are conducted to investigate the effects of volume change on soil-water characteristics of remodeling expansive soil from the field test section in Nanyang, where the Middle Route of the South-to-North Water Diversion project of China passes. A more reasonable formula for volume change correction is derived. The test results indicate that the volume change of expansive soil specimens has significant influence on the soil-water characteristic curve (SWCC) under dehydration path. For the same matric suction, the saturation degree/volumetric water content of the specimens after volume change correction is greater than that before volume change correction, while the difference between them is more distinct in the high suction section. Based on the Fredlund-Xing model and the test results, a SWCC model, which can take the volume change of specimens during dehydration process into account, is developed, and the effect laws of the initial void ratio of the specimens on the parameters of the SWCC model are discussed. Moreover, the behavior of spatial curved surface showing the relationship among water content, suction and void radio is investigated. Considering the volume change of the specimens during dehydration process, the functional relationship between the void ratio and the water content is a cubic polynomial, not linear relation.