Influence of specimen uniformity on mechanical behaviour of unsaturated soil
来源期刊：中南大学学报(英文版)2014年第3期
论文作者：YANG Gang(杨钢) YANG Qing(杨庆) ZHANG Jin-li(张金利)
文章页码：1197 - 1205
Key words：unsaturated soil; remolded specimen; uniformity; pore structure; saturation degree
Abstract: Pressure plate instrument is employed during drying, and unconfined compressive strength test is performed on the unsaturated specimen. Curves of shear force versus shear displacement, and curves of saturation degree versus time are investigated. The results show that the specimens with similar curves of saturation degree versus time have nearly identical mechanical behavior. In particular, the uniform specimens should be chosen within the lower equilibrium saturation degree because steady test results are presented. Further, the conclusion is verified by the repeated test. Thus, the method for distinguishing the uniform unsaturated specimen is obtained. In the light of the method, an improved test process is proposed. The uniform specimens should be chosen by this method under the specific matric suction, and then shear tests are carried out on the chosen unsaturated specimen. Namely, initial value of unsaturated soil is not zero matric suction but a specific suction.
YANG Gang(杨钢), YANG Qing(杨庆), ZHANG Jin-li(张金利)
(Institute of Geotechnical Engineering, Dalian University of Technology, Dalian 116024, China)
Abstract:Pressure plate instrument is employed during drying, and unconfined compressive strength test is performed on the unsaturated specimen. Curves of shear force versus shear displacement, and curves of saturation degree versus time are investigated. The results show that the specimens with similar curves of saturation degree versus time have nearly identical mechanical behavior. In particular, the uniform specimens should be chosen within the lower equilibrium saturation degree because steady test results are presented. Further, the conclusion is verified by the repeated test. Thus, the method for distinguishing the uniform unsaturated specimen is obtained. In the light of the method, an improved test process is proposed. The uniform specimens should be chosen by this method under the specific matric suction, and then shear tests are carried out on the chosen unsaturated specimen. Namely, initial value of unsaturated soil is not zero matric suction but a specific suction.
Key words:unsaturated soil; remolded specimen; uniformity; pore structure; saturation degree
