Study On The Project Character Of Subgrade Compaction Of Unsaturated Cohesive Soil By Test

This paper studied the project character of remoulded, unsaturated and compacted clay.This experiment chose three points of the completed compaction curve as the objects.They were the optimal water content and the bilateral water content corresponding the same value of dry density.Soil-water characteristic curve was measured by pressure plate.Expansion -pressure was measured by three-dimensional expansion instrument. Strenghts of soil samples with controlled suction and stress and the changes of water content before and after shearing is measured by direct shearing. Micro-sensor was used to measure pore air pressure and pore water pressure during the shearing process,on the base of improving conventional triaxial apparatus of the unsaturated soil.This paper studied triaxial compression experments of different water contents,different density and different degree of compaction of soil.Through micro-sensor, the changes of pore air pressure, pore water pressure and the volume of state variables during the shearing process was measured. At the same time, stress-strain and damage of deformation in different physical state of unsaturated soil was got.These experiments accumulating testing data of laboratory,which was important to establish mechanics model of unsaturated soil. This also provided some reference materials and patterns for the study of unsaturated soils in the future.