报告人： Prof Xiong Zhang
Department of Civil and Environmental Engineering, University of Alaska Fairbanks
报告地点：安中大楼A-418
报告时间： 2014年6月18日（星期三）下午3点30分
报告题目： Limitations of Suction-Controlled Triaxial Tests in the Characterization of Unsaturated Soil Behavior
报告人简介
Dr. Xiong Zhang has over 22 years of teaching, research and consulting experience with a wide variety of geotechnical projects. Now he is an Associate Professor in Department of Civil and Environmental Engineering, University of Alaska Fairbanks (UAF). Research interests include Constitutive Modeling of Unsaturated Soils, Advanced Testing Techniques for Unsaturated Soils, Numerical Modeling, Soil Structure Interaction, Foundation on Expansive and Collapsible Soils, Slope Stability and Retaining Walls, Geotechnical Application in Pavement Engineering, Frost Heave and Thaw Weakening, etc. Until now, he has 4 Book Edited, 25 Journal Publications, 21 ASCE Special Publications and 18 Peer-Reviewed Conference Proceedings.
报告简介
Behaviors of unsaturated soils are influenced by many factors and the influences of these factors are usually coupled together. Suction-controlled tiaxial (SCTX) tests are considered to allow researchers to investigate influences of individual variables on unsaturated soils under specified stress path with controls of stresses, pore water and air pressures. However, SCTX tests require sophisticated and therefore expensive equipment. As a result, SCTX tests cannot be justified for ordinary engineering projects. In addition, our recent findings indicated that the SCTX tests in fact cannot control the stress path of an unsaturated soil during loading. This incapability, in combination with complicated loading/collapse behavior of unsaturated soils, makes the long-accepted Divide-and Conquer approach for characterizing unsaturated soil behavior unacceptable. This presentation discusses the limitations of the SCTX tests in the characterization of unsaturated soils. A possible solution to the problem was proposed based on a newly developed modified state surface approach (MSSA). It is proposed that results from undrained (constant water content) tests be used to replace the SCTX tests for the constitutive modeling purpose. Not only can it produce theoretically correct results with much simpler testing equipment, but also significantly reduce the testing time (from 2-3 months/test to 2-3 hours/test). This can potentially leads to extensive applications of unsaturated soil mechanics in routine engineering projects.
浙江大学岩土工程研究所
2014年6月16日