可溶盐对兰州非饱和重塑黄土抗剪强度的影响
发布时间：2018-10-18 15:55
【摘要】：岩土体抗剪强度是分析评价斜坡稳定性的关键指标。为了弄清可溶盐在黄土抗剪特性中的作用程度及控制机制,以兰州重塑黄土为对象,基于直剪试验,研究了黄土抗剪强度及其参数在不同溶滤次数下的变化特征。结果显示,可溶盐对非饱和黄土抗剪强度及黏聚力具有明显非线性弱化作用,而对内摩擦角的影响则相对微弱。其中,抗剪强度与黏聚力随可溶盐的变化规律存在临界分段现象,其降低幅度在溶滤1次时达到最大值,在溶滤5次后近似于0;而降低速率以易溶盐含量2 620 mg/100 g干土为分界值,呈先快后慢的变化特征。上述关系的内在机制是,在溶滤初始阶段,黄土抗剪特性弱化主要源于易溶盐与部分难溶盐分解;随溶滤次数增加,则更多依赖于易溶盐分解与基质吸力减弱。
[Abstract]:The shear strength of rock and soil is the key index to analyze and evaluate the slope stability. In order to understand the effect and control mechanism of soluble salt on the shear resistance of loess, taking Lanzhou remolded loess as an example, based on the direct shear test, the variation characteristics of loess shear strength and its parameters under different dissolved filtration times were studied. The results show that the soluble salt has obvious nonlinear weakening effect on the shear strength and cohesion of unsaturated loess, but the influence on the angle of internal friction is relatively weak. Among them, the shear strength and cohesion with the variation of soluble salt have critical segmental phenomenon, and the decrease of shear strength and cohesion reaches the maximum at the first time of solubilization. After 5 times of leaching, the rate of reduction was approximately 0, and the decreasing rate was at the boundary value of 2620 mg/100 g dry soil, which showed the characteristics of first quick change and then slow change. The intrinsic mechanism of the above relationship is that in the initial stage of dissolved filtration, the weakening of shear resistance of loess is mainly due to the decomposition of soluble salt and part of insoluble salt, and with the increase of leaching times, it is more dependent on the decomposition of soluble salt and the weakening of matrix suction.
【作者单位】： 华北水利水电大学资源与环境学院;中国地质大学(北京)水资源与环境学院;
【基金】：国家自然科学基金项目(No.41372260,No.41402269) 河南省科技创新人才计划(No.154100510006) 华北水利水电大学高层次人才科研启动金(No.40432)~~
【分类号】：TU444
本文编号：2279619
[Abstract]:The shear strength of rock and soil is the key index to analyze and evaluate the slope stability. In order to understand the effect and control mechanism of soluble salt on the shear resistance of loess, taking Lanzhou remolded loess as an example, based on the direct shear test, the variation characteristics of loess shear strength and its parameters under different dissolved filtration times were studied. The results show that the soluble salt has obvious nonlinear weakening effect on the shear strength and cohesion of unsaturated loess, but the influence on the angle of internal friction is relatively weak. Among them, the shear strength and cohesion with the variation of soluble salt have critical segmental phenomenon, and the decrease of shear strength and cohesion reaches the maximum at the first time of solubilization. After 5 times of leaching, the rate of reduction was approximately 0, and the decreasing rate was at the boundary value of 2620 mg/100 g dry soil, which showed the characteristics of first quick change and then slow change. The intrinsic mechanism of the above relationship is that in the initial stage of dissolved filtration, the weakening of shear resistance of loess is mainly due to the decomposition of soluble salt and part of insoluble salt, and with the increase of leaching times, it is more dependent on the decomposition of soluble salt and the weakening of matrix suction.
【作者单位】： 华北水利水电大学资源与环境学院;中国地质大学(北京)水资源与环境学院;
【基金】：国家自然科学基金项目(No.41372260,No.41402269) 河南省科技创新人才计划(No.154100510006) 华北水利水电大学高层次人才科研启动金(No.40432)~~
【分类号】：TU444
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