不同排水条件下砂-黄土界面的剪切力学特性

为了研究异质土在不同排水条件下的力学机理，进行了一系列环剪试验，对单一黄土、单一砂、砂-黄土组成的异质土在剪切力学特性上的差异及其产生机理进行了比较分析。结果表明：在不同排水条件下，砂-黄土组成的异质土在相互接触剪切的过程中，剪切应力变化形态和抗剪强度与单一黄土、单一砂之间存在显著差异，即砂-黄土组成的异质土在其剪切过程中呈现出了黏性土的剪切力学特征；在相同剪切速率条件下，砂-黄土组成的异质土在不同排水条件下的抗剪强度比单一黄土和单一砂的抗剪强度至少降低了71%和51%。不同排水条件下砂-黄土的剪切力学性质出现了差异，其主要原因与剪切面处砂与黄土之间的相互作用以及剪切面处土体内孔隙水状态有关。

Shear Mechanical Properties of Sand-Loess Under Different Drainage Conditions

In order to study mechanical characteristics of heterogeneous soils under different conditions, the authors conducted a series of ring shear tests, and compared the differences of shear mechanical characteristics between loess, sand, and heterogeneous soils composed of sand and loess. A comparative analysis was carried out on the differences and their generation mechanisms. The study results showed that under different drainage conditions, the change form of shear stress and shear strength of heterogeneous soil composed of sand and loess were significant different from those of loess or sand during the mutual shearing process. At the same shearing rate, when compared with those of single loess and single sand, the shear strength of sand-loess under different drainage conditions was decreased by 71% and 51%, respectively. During the shearing process, the heterogeneous soil composed of sand and loess presented the shearing mechanical characteristics of cohesive soil. The mechanical characteristic differences between heterogeneous soils and single loess or single sand under different drainage conditions are mainly related to the interaction between sand and loess on the shearing surface and pore water state inside soil body.