Experimental Research On Critical State Characteristics Of Unsaturated Remolded Expansive Soils

This thesis is a part of the project of"Research of structures and strength of unsaturated expansive soils"supported by National Natural Science Foundation of China (No.40374047). A series tests including drainage shear, undrainage shear and suction-controlled consolidation of Guangxi expansive soils were performed, and the critical state characteristics of Guangxi unsaturated expansive soils was studied based on the principle of unsaturated soil mechanics. The main results are obtained as follows:1. The critical state characteristics of unsaturated soils was studied by the trial-axial test results, and the infection factors of critical state of unsaturated soils were analyzed. Based on the experiment data, the critical state equation of unsaturated soils is used to calculate the critical state curves.2. A number of suction-controlled consolation test were performed on the remolded Guangxi expansive soils. The influence of suction on unsaturated soils behavior was investigated. The consolation characteristics for different degrees of saturation were studied and revealed yield characteristics in p-s plane of unsaturated soils which were controlled by different suction.3. The influence of macrostructure and microstructure to the deformation of unsaturated soils was studied. The elaso-plastic model was used to analyze the characteristics of unsaturated soils, and model parameters were calculated by the experiment data. The calculation results of LC curves are in good agreement with the experimental data.