非饱和红粘土抗剪强度特性研究及其应用

【作者】 曾志姣；

【导师】 张家生；

【作者基本信息】 中南大学 ， 岩土工程， 2008， 硕士

【摘要】 非饱和土是当今国内外土力学研究的热点和难点,而抗剪强度是非饱和土研究的重要内容。本文对前人在非饱和土抗剪强度理论以及强度试验方面的研究成果进行了系统的文献阅读和综述,通过试验研究了非饱和红粘土的抗剪强度特性并将其应用于非饱和土坡稳定性的求解。本文的研究内容主要有以下几点:1.综述了研究非饱和土问题的必要性,非饱和土的基本特性和基质吸力的概念,以及非饱和土问题研究的历史和现状。2.抗剪强度是非饱和土重要的研究领域之一,本文对非饱和土抗剪强度理论及强度试验研究历史与现状作了分析总结。3.以湖北咸宁地区的非饱和红粘土为研究对象,利用GDS全自动三轴及非饱和试验系统,在控制吸力方式下进行非饱和土的固结排水剪切试验,研究了其抗剪强度与基质吸力之间的关系,建立了针对此非饱和红粘土的抗剪强度公式。4.粘性土土坡受降雨影响非常显著,很多土坡常在雨季发生滑坡,最重要的原因就是含水量的增加降低了土的吸力从而降低了土的抗剪强度。本文以一简单边坡为例,计算分析了在降雨情况下考虑非饱和非稳定渗流所引起的吸力变化以及基质吸力对强度影响时其稳定系数随时间的变化情况。更多还原

【Abstract】 The study of unsaturated soil is the hotspot and difficulty of soil mechanics,and the study of strength of unsaturated soil is quite significant.In the paper,formers’ works in strength theory and test of unsaturated soil have been summarized.The shear properties of unsaturated red clay is studied by test and applied to the solution of soil slope stability.The primary works in this paper are presented as follows:1. The importance of the study of unsaturated soils is emphasized.The basic characteristics of unsaturated soils,concept of matrix suction,and the research history and present situation of unsaturated soils are simply introduced.2. The shear strength is one of the most important research fields of the unsaturated soils. The research history and present situation of strength theory and test of unsaturated soils are simply introduced.3. With matrix suction of specimen controlled,the consolidated drained triaxial tests were carried out for the unsaturated red clay of Xianning in Hubei province by triaxial test system for unsaturated soil to study the relationship between shear strength and matrix suction of specimen and present the formula on strength of the unsaturated red clay.4. Slope stability of cohesive soil is significantly influenced by rainfall.The most important cause of landslide taking place in rainy season is that the increase of moisture content makes the matrix suction of soil decreased thus reduces the shear strength.With the change of matrix suction caused by unsaturated unsteady seepage and influence of matrix suction on shear strength considered,the stability of a simple slope under rainfall is calculated.更多还原