水位变化条件下二元结构库岸边坡稳定性研究

发布时间：2018-03-13 14:03

本文选题：水位变化　切入点：库岸边坡　出处：《昆明理工大学》2017年硕士论文　论文类型：学位论文

【摘要】：水对边坡稳定性有着重要的影响,世界上大型滑坡的发生几乎都与水有关,而水对边坡稳定性影响主要表现为水位变化和降雨。水位变化作用对边坡稳定性影响比较复杂,随着库水位变化,变坡体内的地质环境和受力状态等会发生变化;一方面随着库水位的上升,边坡中岩土体抗剪强度降低,孔隙水压力增大,另一方面随着库水位的下降,坡体中渗流力较大,静水压力减小。二元结构边坡为库岸边坡中最为常见的一类边坡,本文从实际问题出发,研究库水位变化对库岸二元结构边坡渗流及稳定性影响的问题对我国库岸边坡稳定性的研究及水电工程的运行安全具有重要的意义。本文以阿海水库新建边坡为研究对象,从定性与定量两方面研究与探讨库水位变化对边坡稳定性影响。首先从理论上出发,分析边坡发生变形破坏的机理,进而从定性的角度分析水位变化对库岸边坡稳定性的影响,最后进行定量分析,主要从库水位变化的速率、渗透系数的变化及水位变化的幅度等三个方面,研究其对二元结构库岸边坡稳定性的影响规律,并与以自阿海水库蓄水以来新建滑坡的监测数据进行对比分析,得出的主要研究成果如下:(1)随着库水位上升边坡孔隙水压力逐渐增大;随着库水位下降边坡孔隙水压力逐渐减小。且库水位下降的速率越大,孔隙水压力变化越大。(2)库水位在快速上升的过程中二元结构库岸边坡整体与局部稳定性变化呈现出先增大后减小再增大的变化规律;而在库水位缓慢变化过程中边坡整体与局部稳定性变化呈现出先减小后增大的变化规律,且库水位上升的速率越快边坡稳定性安全系数变化的越快;总体来说随着库水位的上升边坡稳定性是减小的。(3)库水位在下降的过程中二元结构库岸边坡整体与局部的稳定性安全系数呈现出先减小后增大的变化规律,且库水位下降的速率越快,边坡稳定性安全系数的变化越大。(4)在库水位反复上升与下降作用下,二元结构库岸边坡存在两种潜在破坏模式,即边坡前缘局部滑动破坏和沿着边坡滑带土的滑动。当边坡前缘滑体局部滑动破坏后,后缘由于失去支撑发生整体牵引式滑坡。
[Abstract]:Water has an important influence on slope stability. The occurrence of large landslide in the world is almost related to water, while the influence of water on slope stability is mainly manifested by water level change and rainfall. The influence of water level change on slope stability is quite complex. With the change of reservoir water level, the geological environment and stress state of the slope will change, on the one hand, with the rise of reservoir water level, the shear strength of rock and soil in the slope will decrease, the pore water pressure will increase, on the other hand, with the decrease of reservoir water level, The seepage force in the slope is large and the hydrostatic pressure is reduced. The binary structure slope is the most common type of slope in the bank slope. It is of great significance to study the influence of reservoir water level change on the seepage and stability of dual structure slope of reservoir bank in our country and the operation safety of hydropower project. In this paper, the newly built slope of Ahai Reservoir is taken as the research object. The influence of reservoir water level change on slope stability is studied from qualitative and quantitative aspects. Firstly, the mechanism of slope deformation and failure is analyzed theoretically, and then the influence of water level change on slope stability is analyzed qualitatively. Finally, the quantitative analysis is carried out, mainly from three aspects: the change rate of reservoir water level, the change of permeability coefficient and the range of water level change, the influence law on the stability of bank slope of dual structure reservoir is studied. The main research results are as follows: 1) the pore water pressure of the slope increases gradually with the rise of water level of the reservoir. With the decrease of reservoir water level, the pore water pressure of slope gradually decreases. The larger the change of pore water pressure is, the greater the variation of reservoir water level is in the process of rapid rising of reservoir water level. The whole and local stability changes of bank slope of binary structure reservoir show the law of increasing first and then decreasing and then increasing. In the process of slowly changing of reservoir water level, the whole and local stability changes of slope show the law of decreasing first and then increasing, and the faster the rate of rise of reservoir water level is, the faster the safety factor of slope stability changes. Generally speaking, with the rise of reservoir water level, the slope stability is reduced. (3) in the process of decreasing reservoir water level, the overall and local stability safety factor of the bank slope of dual structure reservoir shows the law of first decreasing and then increasing. Moreover, the faster the water level drops, the greater the change of slope stability safety factor is. (4) under the action of repeatedly rising and falling reservoir water level, there are two potential failure modes on the bank slope of dual structure reservoir. That is, the local sliding failure of the front edge of the slope and the sliding of the soil along the slope slip zone. After the local sliding failure of the landslide body in the front edge of the slope, the whole traction landslide occurs due to the loss of support in the rear edge.
【学位授予单位】：昆明理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P642.22

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