MODEL FITTING AND STRENGTH CHARACTERISTICS OF CRITICAL STATE FOR EXPANSIVE SOIL

According to Mengzi expansive soil, consolidated drained tests and undrained tests are carried on under the saturated and remolded condition. The stress-strain characteristics of saturated soil are researched systematically under different consolidation pressure, initial dry density, initial water content, shearing rate and drainage condition. The inherent unity of diversity of shearing strength for the same samples is measured by different experimental methods and is indicated according to the normalization of critical state test results. The failure lines in p'-q- space of remolded saturated expansive soil under consolidated drained and undrained condition are attained. The hyperbolic curve model can fit well the inferior hardening stress-strain curve. The exponential curve model can fit the inferior soft stress-strain curve. The test results can provide technical parameters and theoretical help for shearing strength variation of slope during rainfall and strength state of soil structure in normal water level.