四川木里菜籽湾滑坡形成演化机制及稳定性评价研究

发布时间：2018-06-26 09:34

本文选题：形成演化机制 + 化学分析　；参考：《成都理工大学》2015年硕士论文

【摘要】：菜籽湾滑坡位于四川省木里县下麦地乡菜籽沟北侧,方量约260万m3。它是在崩坡积、残坡积物中发育的一个特大型覆盖层滑坡,属中高位滑坡。原省道216线即从该滑坡上部通过。该滑坡变形强烈,变形破坏现象丰富且变形破坏方式十分复杂。研究该滑坡变形破坏及形成演化机制对于探索大型覆盖层滑坡形成机制及山区沟谷地貌演化具有理论意义;同时对改建工程选线方案具有重要工程指导意义。本文通过对该滑坡变形破坏现象的详细调查测绘,滑坡区表层不连续分布红土的物理性质、化学成分、石英颗粒表面形貌特征的测试,滑坡形成演化各阶段的数值模拟计算及现今变形斜坡稳定性的定量分析计算。取得了如下成果:1.阐明了滑坡的变形破坏方式。下部侧向滑动区是在中部滑塌解体区大体量物质滑走以后,从两侧侧向下滑形成;中部滑移解体区是大体量物质滑走后形成的巨大凹腔、上部滑移解体区是受沟水冲刷及下方滑体变形影响产生。2.揭示了菜籽湾滑坡形成演化的阶段。滑坡形成演化经历了三个阶段:早期滑坡形成一巨大滑塌凹腔→下部侧向滑动、锁口→残留凹腔上方逐级滑塌后退、并超覆于下部滑体。早期滑坡是逐级后退形成的,形成时间在菜籽沟之后,上个世纪70年代以前,规模达百万方级。3.验证了形成演化阶段的合理性。模拟结果表明早期滑塌腔的范围宽度与根据变形破坏现象推测的结果接近;滑塌腔形成后,滑坡左右边界附近滑体有侧向位移矢量;滑塌腔后部滑体剪应变增量已达失稳量级。4.评价了菜籽湾现今变形斜坡的稳定性状况。极限平衡法的结果表明天然工况下变形斜坡基本稳定,暴雨工况下不稳定;强度折减法的结果表明随着抗剪强度削弱,塑性区呈逐渐贯通的发展趋势,暴雨工况下的安全储备系数不足。目前滑坡仍在持续变形,今后若无有效支护措施,滑坡将向上方继续发展直至失稳。欲使改建公路安全通过该滑坡地段,必须采取有效支护或采用遂线方案绕避。
[Abstract]:Rapeseed Bay landslide is located in Muli County, Sichuan Province, Xiamaixiang rapeseed ditch north side, about 2.6 million m3 square. It is a very large overburden landslide developed in the caving and residual slope deposits, which belongs to the middle and high level landslide. The original dart 216 line passes through the upper part of the landslide. The landslide has strong deformation, rich deformation and failure phenomenon and complex deformation and failure mode. The study of the deformation, failure and evolution mechanism of the landslide is of theoretical significance for exploring the formation mechanism of large overburden landslide and the evolution of mountain valley geomorphology, and also has important engineering guiding significance for the line selection scheme of reconstruction project. Through the detailed investigation and mapping of the deformation and failure phenomenon of the landslide, the physical properties, chemical composition and surface morphology of quartz particles in the surface discontinuous distribution of laterite in the landslide area are measured. Numerical simulation of landslide formation and evolution and quantitative analysis of stability of deformation slope. The following results have been achieved: 1. The deformation and failure mode of landslide is expounded. The lower lateral slip zone is formed from both sides after the large mass material slips away in the middle part of the landslide area, and the middle slip area is a huge cavity formed after the large mass material slips away. The upper slip area is affected by the erosion of the trench water and the deformation of the lower slip body. The stage of formation and evolution of rapeseed bay landslide is revealed. The formation and evolution of the landslide underwent three stages: the formation of a large cavities in the early landslide and lateral sliding in the lower part of the cavity, and the collapse and retrogression of the upper part of the residual cavity of the lock mouth, which overlay the lower part of the slide body. The early landslides were gradually retreated, after rapeseed trenches, and before the 1970s, the scale reached million-square. 3. The rationality of the stage of formation and evolution is verified. The simulation results show that the range width of the early cavities is close to the predicted results according to the deformation and failure phenomena; after the cavities are formed, there are lateral displacement vectors in the sliding bodies near the left and right boundaries of the landslide; the shear strain increment of the sliding bodies in the back part of the cavities has reached the order of. 4. The stability of rapeseed bay deformation slope is evaluated. The results of limit equilibrium method show that the deformation slope is basically stable under natural conditions and unstable under heavy rain conditions, and the results of strength reduction method show that the plastic zone is gradually penetrating with the weakening of shear strength. The safety reserve coefficient under heavy rain condition is insufficient. At present, the landslide is still deforming, and if there is no effective supporting measures in the future, the landslide will continue to develop upwardly until it is unstable. In order to make the reconstructed highway pass safely through the landslide, it is necessary to take effective support or adopt the tunnel scheme to avoid it.
【学位授予单位】：成都理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P642.22

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