非饱和黄土的抗拉特性研究

Property of tensile strength of unsaturated loess

采用劈裂法试验获得了非饱和原状黄土的抗拉强度,并用滤纸法对劈裂破坏后的黄土试样进行了基质吸力的测定,分析了含水率和基质吸力对抗拉强度的影响,同时探讨了抗拉强度与粘聚力的关系。试验结果表明:非饱和原状黄土的抗拉强度很小,抗拉强度随含水率的增大而减小,基本为负的指数函数关系;抗拉强度随基质吸力的增大而增大,两者之间呈幂函数关系;当土体含水率小于缩限时,抗拉强度的增大幅度远远小于基质吸力;抗拉强度随粘聚力的增大而增大,两者之间为良好的线性关系,此种线性关系应是土体的固有性质。

The tensile strength of unsaturated natural loess was determined by the splitting method.The matric suction of loess sample after fracturing was measured using the filter paper method.The effects of water content and matric suction on the tensile strength were analyzed and the relationship between the tensile strength and cohesion was discussed.The results showed the tensile strength of unsaturated natural loess is very small and it decreases with the increasing of water content in a negative exponential function;the tensile strength increases with the increasing of matric suction in a power function;the increasing rate of tensile strength is far less than that of matric suction when water content is less than shrinkage limit of soil sample;and the tensile strength increases with the increasing of cohesion in a good linear relationship,and this relationship is the intrinsic characteristic of natural loess.