三峡库区堆积层滑坡滑动面特征及稳定性研究

发布时间：2018-01-23 12:08

本文关键词： 三峡库区滑坡滑动面微观结构滑坡稳定性　出处：《武汉工程大学》2015年硕士论文　论文类型：学位论文

【摘要】：我国的滑坡具有规模大、成灾机制复杂、灾害损失大、防治难度高等特点,且系统研究和治理起步较晚,其复杂多样性使预测、治理变得困难。要进一步深化对滑坡特性的认识,应不断拓宽滑坡滑动面的研究领域,总结分析影响滑动面强度的本质原因。由于滑坡滑动面的物质组成、微观结构多种多样,因此揭示滑动面的宏观和微观特征,进而分析其稳定性,才能为滑坡的防治工程提供准确的理论依据。论文主要研究内容及结论如下:(1)对不同的滑坡滑动面几何形态特征进行分析。从滑动面空间几何形态特征、滑动面擦痕特征两方面举例分析三峡库区堆积层滑坡滑动面几何形态特征。以花园北养鸡场滑坡为例,该滑坡滑动面擦痕有镜面状、线性擦痕、凸凹不平状和组合形态,不同的滑动阶段会产生不同形态的擦痕。(2)对滑坡滑动面矿物组成及微观结构特征进行分析。采用扫描电子显微镜和X射线衍射仪分析花园北养鸡场滑坡滑动面的微观结构特征、元素种类及含量、矿物组合,揭示了该滑动面的矿物组成以大量蒙脱石为主,遇水膨胀、软化,剪切强度低、结构较松散,同时微孔隙和微裂隙大量发育,属于易滑岩组。(3)对不同形态的滑动面进行稳定性分析。采用极限平衡法计算出各种形态滑动面的稳定性系数,对比分析后得出结论:圆弧型滑动面中,随圆弧半径的减小稳定性系数先减小后增大;直线型滑动面中,不同前缘倾角形态下的稳定性系数逐渐增大;阶梯型滑动面中,不同台阶数形态下的稳定性随台阶个数的增多而逐渐增大;组合型滑动面中,含有1个台阶不同圆弧半径的稳定性系数随圆弧半径的减小而逐渐增大,含有2个台阶不同圆弧半径的稳定性系数随圆弧半径的减小先减小再增大。(4)对花园北养鸡场滑坡滑动面形态与稳定性进行分析。试验得出不同含水率下的黏聚力、内摩擦角值,采用极限平衡法计算其稳定性。含水率对黏聚力、内摩擦角值有较大影响,进而影响花园北养鸡场滑坡的稳定性:含水率较低时,该滑坡稳定性随着含水量增大而逐渐增大;高含水率状态下,该滑坡稳定性随着含水量增大而显著降低;其中界限含水率为18.68%,滑坡稳定性达到最大值。不同类型的滑动面对该滑坡稳定性也有影响:直线型滑动面最不稳定,其次是圆弧型,台阶型滑动面稳定性比圆弧型略高,组合型滑动面最稳定。
[Abstract]:Landslide in China has the characteristics of large scale, complex disaster formation mechanism, large disaster loss, high difficulty in prevention and control, and the systematic research and management started late, and its complex diversity makes prediction. In order to deepen the understanding of landslide characteristics, it is necessary to continuously broaden the research field of landslide sliding surface and analyze the essential reasons that affect the strength of landslide surface, because of the material composition of landslide sliding surface. The microstructures are varied, so the macroscopic and microscopic characteristics of the sliding surface are revealed, and the stability of the sliding surface is analyzed. In order to provide an accurate theoretical basis for landslide prevention and control engineering. The main contents and conclusions of this paper are as follows: 1) the geometric morphological characteristics of different landslide sliding surface are analyzed. Two examples are given to analyze the geometric features of the sliding surface of the accumulation layer in the three Gorges Reservoir area. Taking the landslide in the north farm of Huayuan as an example, the sliding surface of the landslide has a mirror surface and a linear scratch. Uneven shape and combination form. Different sliding stages produce different forms of scratches. The mineral composition and microstructure of landslide slide surface were analyzed. The microstructure of landslide slide surface was analyzed by scanning electron microscope and X-ray diffractometer. The mineral composition of the sliding surface is mainly composed of montmorillonite, water swelling, softening, low shear strength, loose structure, and a large number of micropores and microfissures developed at the same time, the types and contents of elements and mineral assemblages show that the mineral composition of the sliding surface is mainly montmorillonite. The stability of sliding surfaces of different forms is analyzed by using limit equilibrium method. The stability coefficients of sliding surfaces of various forms are calculated by using limit equilibrium method, and the conclusion is drawn by comparison and analysis: in the circular arc sliding surface. The stability coefficient decreases first and then increases with the decrease of arc radius. In the linear sliding surface, the stability coefficient increases gradually under the shape of different leading edge inclination. In the stepped sliding surface, the stability increases with the increase of the number of steps. In the combined sliding surface, the stability coefficient of different arc radii with one step increases with the decrease of arc radius. The stability coefficient of two steps with different arc radius decreases first and then increases with the decrease of arc radius. The shape and stability of landslide sliding surface in Huayabei chicken farm were analyzed, and the cohesive force under different moisture content was obtained. The internal friction angle value is calculated by the limit equilibrium method. The moisture content has great influence on the cohesion and internal friction angle value, and then affects the stability of the landslide in the north chicken farm: when the moisture content is low. The stability of the landslide increases with the increase of water content. Under the condition of high water content, the stability of the landslide decreases significantly with the increase of water content. The limit water content is 18.68 and the landslide stability reaches the maximum. The stability of the landslide is also affected by different types of sliding: the linear sliding surface is the most unstable, followed by the arc type. The stability of step sliding surface is slightly higher than that of circular arc type, and that of combined sliding surface is the most stable.
【学位授予单位】：武汉工程大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P642.22

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