持续降雨入渗非饱和黏土边坡失稳机理及其应用研究 Alternative Title Instability Mechanism and Application Analysis of Partially Saturated Clay Slope under Sustained Rainfall Infiltration 刘子振 Thesis Advisor 言志信 2014-11-26 Degree Grantor 兰州大学 Place of Conferral 兰州 Degree Name 博士 Keyword 持续降雨 非饱和黏土边坡 入渗方式 失稳机理 模型试验 Abstract 本文将非饱和-饱和土边坡极限平衡理论和土壤水渗流理论相互融合，运用强度折减数值计算方法，并结合模拟试验和工程实际进行分析，主要进行了以下几方面的研究： 首先，本文结合降雨诱发工程边坡破坏的现状，探讨了雨水入渗作用下的边坡黏土工程特性和边坡稳定机理。将不同含水量的黏土进行室内试验，获得了不同含水量黏土的抗剪强度及相关参数，并通过基质吸力试验数据拟合发现该黏土SWCC曲线指数拟合式更合理。 接着，探讨了持续降雨条件下坡面雨水入渗深度以及入渗方式。结合黏土饱和入渗原理和Green-Ampt入渗方式，考虑坡内黏土初始含水量相同和有规律变化两种情况，分别计算雨水饱和入渗与非饱和入渗下坡面积水时间、积水时的入渗深度和入渗率。 进而，研究了持续降雨过程引起的含水量和容重增加、粘聚力和内摩擦角减小，从而诱发土坡的安全系数快速下降。通过各种黏土屈服准则参数的相互变换，可得到持续降雨工况下的黏土内摩擦角Φ=16.5度可作为其屈服准则选取或调整的临界点。 然后，通过边坡模拟试验直观展现了模型边坡在持续降雨工况下的变形破坏过程，验证了持续降雨入渗过程存在非饱和入渗方式。 Other Abstract Based on the combination of the limit equilibrium theory and the theory of soil-water seepage of partially saturated and saturated clay slope, the slope stability was analyzed by the strength reduction combining with relevant engineering and related model test. The research was done mainly in the following aspects: First of all, combining with the instability characteristics of engineering slope induced by rainfall, the engineering characteristics of clay slope and the mechanics theory due to the influence of rainfall were discussed. The shear strength parameters of clay under different moisture content were obtained through the related experiment of clay. According to the experimental results of testing matric suction, the SWCC of clay fitted as exponential curve was more reasonable. Secondly, The infiltration depth and infiltration mode were analyzed under rainfall infiltration into clay slope. Combining with the saturated infiltration theory and the Green-Ampt infiltration model, the ponding time on the slope’s surface and the ponded infiltration depth and infiltration rate could be calculated for saturated and unsaturated infiltration respectively, when the initial moisture content of clay was the same or changeable regularly. Thirdly, after the sustained rainfall infiltration into clay slope, the moisture content and the bulk density of clay would increase with the decreasing of the cohesion and internal friction angle of clay. Therefore, the slope safety coefficient would decrease rapidly which leaded to slope instability eventually. Through the related transformation of various types of clay yield criterion, we could obtain the critical point of choosing or adjusting different soil yield criterion by calculating the internal frictional angle of clay, Φ=16.5, under sustained rainfall. Then, there was an intuitive test model of clay slope which showed the deformation and failure process of the slope model under the sustained rainfall infiltration. The test result showed that there was an unsaturated infiltration process in clay slope under sustained rainfall. The matric suction of soil could be obtained in the different depth of slope top and middle slope and slope toe under sustained rainfall. The safety coefficient based on potential slip surface could be calculated according to determining the depth of slope top or middle slope respectively. The safety factor was the least with the potential slip surface listed at about 15cm of infiltration d... URL 查看原文 Language 中文 Document Type 学位论文 Identifier https://ir.lzu.edu.cn/handle/262010/226647 Collection 土木工程与力学学院 Recommended CitationGB/T 7714 刘子振. 持续降雨入渗非饱和黏土边坡失稳机理及其应用研究[D]. 兰州. 兰州大学,2014.
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