基于CD三轴试验的非饱和黄土吸应力强度参数确定

发布时间：2018-03-06 23:03

本文选题：非饱和黄土　切入点：有效强度参数　出处：《工程地质学报》2017年01期 　论文类型：期刊论文

【摘要】：非饱和土强度参数的确定是其能够用于工程实际的关键。目前公认的非饱和土强度理论有Bishop的单变量理论、Fredlund的双变量理论以及Lu Ning的吸应力强度理论。其中吸应力强度理论基于吸应力特征曲线,可直接由常规三轴试验得出,回避了测定基质吸力的问题,便于在工程实际中推广。本文通过不同含水率的三轴CD试验,测得陕西泾阳原状Q2(L5)黄土的有效强度参数。结果表明,该黄土不同含水率的有效内摩擦角基本接近;有效黏聚力随含水率的增大呈指数递减,当含水率超过塑限时,黏聚力趋于定值。根据有效黏聚力和吸应力的关系,可以获得吸应力和含水率的关系,即吸应力特征曲线,并通过拟合得出吸应力函数,以及非饱和土强度表达式。
[Abstract]:The determination of the strength parameters of unsaturated soil is the key to its application in engineering practice. At present, the accepted theory of unsaturated soil strength includes Bishop's univariate theory, Fredlund's bivariate theory and Lu Ning's theory of absorptive stress intensity. The theory of force strength is based on the characteristic curve of absorbing stress. It can be obtained directly from conventional triaxial test, which avoids the problem of measuring the suction of matrix and is easy to be popularized in engineering practice. In this paper, the effective strength parameters of Shaanxi Jingyang undisturbed Q2L5) loess are measured by triaxial CD test with different moisture content. The results show that, The effective internal friction angle of the loess with different moisture content is close, and the effective cohesion decreases exponentially with the increase of moisture content. When the moisture content exceeds the plastic limit, the cohesion force tends to be fixed. According to the relationship between effective cohesion force and absorptive stress, The relationship between absorptive stress and moisture content, I. e., the characteristic curve of absorptive stress, can be obtained, and the absorptive stress function and the expression of unsaturated soil strength can be obtained by fitting.
【作者单位】：长安大学地质工程与测绘学院;中国地质调查局西安地质调查中心国土资源部黄土地质灾害重点试验室;太原理工大学矿业工程学院;
【基金】：973项目(2014CB744701) 中央高校优博项目(310826150005)资助
【分类号】：TU411;TU444

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