非饱和膨胀土剪切强度参数对比试验研究  

Experimental Comparison Study on Shear Strength Parameters of Unsaturated Expansive Soil

作　　者：姜彤[1] 张俊然[2] 陈宇[1] 

机构地区：[1]华北水利水电大学岩土工程与水工结构研究院,河南郑州450045 [2]上海大学,上海200444

出　　处：《华北水利水电学院学报》2013年第4期1-6,129,共6页North China Institute of Water Conservancy and Hydroelectric Power

基　　金：国家自然科学基金(51109082;41140030);郑州市创新型科技人才培育计划领军人才项目(10LJRC185);水利部公益性行业科研专项经费资助项目(201301034)

摘　　要：通过控制基质吸力的直剪和三轴试验,研究非饱和膨胀土强度参数随基质吸力的变化规律.试验结果表明:直剪和三轴试验得出的强度参数随基质吸力的变化规律基本相同,黏聚力随基质吸力的增加而增加,内摩擦角随基质吸力的增加而有所减小.非饱和土的内摩擦角并非常数,也受基质吸力大小的影响,当基质吸力小于或等于土样的进气值时,与基质吸力有关的内摩擦角保持不变,而土样内摩擦角随基质吸力的增大而减小.直剪试验得出强度参数相对三轴试验得出的强度参数偏大.In this paper, a series of suction-controlled direct tests and tri-axial tests are carried out to study the shear strength parameters of unsaturated expansive soils. Tests are performed on remolded expansive soil under different matrix suctions condition. The resuits show that the strength parameters derived from direct shear and tri-axial tests have the same variation with suction. Cohesion increases with increasing matrix suction. Internal friction angle decreases with increasing the suction. The internal friction angle of unsaturated soil is not a constant; however, it is also controlled by suction. When matrix suction is less or equal to the air entry value of soil sample, the suction friction angle is a constant, but the internal friction angle decreases with increasing the suction. The strength pa- rameters obtained from the direct shear tests are larger than those from tri-axiat tests. Results in this paper are important for the theory study of unsaturated soil.

关 键 词：非饱和膨胀土 基质吸力 强度 直剪试验 三轴试验 

分 类 号：TU443[建筑科学—岩土工程]