Abstract
Unsaturated soil can be simulated to elasto-plastic material. Based on the test results of suction controlled triaxial test on compacted kaolin clay, theoretical initial yield function and subsequent loading function are induced. Then the theory is examined by stress-probe test. In this paper triaxial stress state is defined by three stress components, they are, effective average principal stress, p=σm-ua, effective suction stress, f(S)=χ(ua-uw) at failure condition, and deviator stress, q=σ1-σ3, in which ua and uw are pore air and pore water pressure, respectively. Only one loading function similar to Original Cam Clay is obtained from the theory, on the other hand, results of stress-probe test indicate the presence of additional yield surface like failure surface besides one theoretically predicted.
