边坡渗流室内模型试验分析
发布时间：2018-12-10 10:32
【摘要】：我国是一个地质灾害多发的国家,其中边坡灾害占到了很大比例。进入新世纪以后,我国经济持续高增长,各地工程建设的增多,导致地质灾害呈有增无减的趋势。而在诱发边坡滑坡的众多因素中,降雨尤其是强降雨是诱发边坡失稳破坏这一地质灾害的最重要因素。入渗过程改变了坡体内部含水率,导致土压力、孔隙水压力等发生变化,使土体抗剪强度降低,边坡稳定性下降。论文主要研究内容如下:(1)设计降雨入渗模型试验,在不同监测点布设处、不同降雨时间等条件下,通过对坡体内部含水率、孔隙水压力、土压力等的变化情况进行分析,得到边坡降雨入渗规律。选用光纤光栅传感器和多通道光纤光栅解调仪设计了一套监测系统,并应用到了边坡降雨入渗模型试验之中。在LabVIEW开发环境下,开发了一套监测软件,实现了对试验数据的采集和处理。(2)试验数据表明,降雨入渗过程中,由于降雨入渗量与泥沙侵蚀量的相对关系,坡体内部土压力会有一个先减小再增大的过程。且降雨结束后,坡体内部的应力值均比初始应力大。而孔隙水压力在降雨入渗过程中,开始无明显变化,随着入渗的进行,其值逐渐增大。之后坡顶土体由非饱和趋于饱和,且随着饱和区的向下扩张,坡顶下方区域含水率不断增大,直至达到饱和状态。试验数据表明,在无任何护坡措施的情况下,坡顶位移变形较大,应重点关注。(3)以边坡降雨入渗模型试验为背景,通过有限元数值模拟软件PLAXIS,采用考虑基质吸力和不考虑基质吸力两种方法,模拟了边坡降雨入渗过程。并从初始孔压场、不同降雨时刻边坡渗流场、孔压场等方面对比分析了以上两种模拟方法的差异,将模拟结果与模型试验数据进行对比,最后得出了对于不存在地下水的模型边坡而言,采用不考虑吸力的模拟方法得到的结果更为符合实际的结论。
[Abstract]:China is a country prone to geological disasters, in which slope disasters account for a large proportion. After entering the new century, our country's economy keeps on high growth and the construction of various projects increases, which leads to the increasing trend of geological disasters. Among the many factors inducing slope landslide, rainfall, especially strong rainfall, is the most important factor to induce slope instability and damage. The infiltration process changes the moisture content in the slope, which leads to the change of soil pressure and pore water pressure, so that the shear strength of the soil decreases and the slope stability decreases. The main contents of this paper are as follows: (1) the rainfall infiltration model test is designed. Under the conditions of different monitoring points and different rainfall time, the variation of water content, pore water pressure and earth pressure in slope body are analyzed. The rainfall infiltration law of slope is obtained. A monitoring system is designed by using fiber grating sensor and multi-channel fiber grating demodulator, and applied to the slope rainfall infiltration model test. In the environment of LabVIEW, a set of monitoring software is developed to collect and process the test data. (2) the experimental data show that the relative relationship between rainfall infiltration amount and sediment erosion amount in the process of rainfall infiltration. There will be a process of decreasing and then increasing the earth pressure in the slope. After the rainfall, the stress inside the slope is larger than the initial stress. However, the pore water pressure does not change obviously in the process of rainfall infiltration, and its value increases gradually with the infiltration. Then the topsoil tends to be saturated from unsaturated to saturated, and with the downward expansion of the saturated area, the water content of the area below the top increases continuously, until the saturated state is reached. The experimental data show that, without any slope protection measures, the displacement of the top of the slope is large and should be paid more attention. (3) based on the rainfall infiltration model test of the slope, the finite element numerical simulation software PLAXIS, is used to simulate the slope. The infiltration process of slope rainfall was simulated by considering the matrix suction and not considering the matrix suction. The differences of the above two simulation methods are compared and analyzed from the aspects of initial pore pressure field, slope seepage field at different rainfall time, pore pressure field and so on, and the simulation results are compared with the model test data. Finally, it is concluded that for the model slope without groundwater, the results obtained by using the simulation method without considering suction are more in line with the actual conclusion.
【学位授予单位】：中国地质大学(北京)
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU411
，
本文编号：2370426
[Abstract]:China is a country prone to geological disasters, in which slope disasters account for a large proportion. After entering the new century, our country's economy keeps on high growth and the construction of various projects increases, which leads to the increasing trend of geological disasters. Among the many factors inducing slope landslide, rainfall, especially strong rainfall, is the most important factor to induce slope instability and damage. The infiltration process changes the moisture content in the slope, which leads to the change of soil pressure and pore water pressure, so that the shear strength of the soil decreases and the slope stability decreases. The main contents of this paper are as follows: (1) the rainfall infiltration model test is designed. Under the conditions of different monitoring points and different rainfall time, the variation of water content, pore water pressure and earth pressure in slope body are analyzed. The rainfall infiltration law of slope is obtained. A monitoring system is designed by using fiber grating sensor and multi-channel fiber grating demodulator, and applied to the slope rainfall infiltration model test. In the environment of LabVIEW, a set of monitoring software is developed to collect and process the test data. (2) the experimental data show that the relative relationship between rainfall infiltration amount and sediment erosion amount in the process of rainfall infiltration. There will be a process of decreasing and then increasing the earth pressure in the slope. After the rainfall, the stress inside the slope is larger than the initial stress. However, the pore water pressure does not change obviously in the process of rainfall infiltration, and its value increases gradually with the infiltration. Then the topsoil tends to be saturated from unsaturated to saturated, and with the downward expansion of the saturated area, the water content of the area below the top increases continuously, until the saturated state is reached. The experimental data show that, without any slope protection measures, the displacement of the top of the slope is large and should be paid more attention. (3) based on the rainfall infiltration model test of the slope, the finite element numerical simulation software PLAXIS, is used to simulate the slope. The infiltration process of slope rainfall was simulated by considering the matrix suction and not considering the matrix suction. The differences of the above two simulation methods are compared and analyzed from the aspects of initial pore pressure field, slope seepage field at different rainfall time, pore pressure field and so on, and the simulation results are compared with the model test data. Finally, it is concluded that for the model slope without groundwater, the results obtained by using the simulation method without considering suction are more in line with the actual conclusion.
【学位授予单位】：中国地质大学(北京)
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU411
，
本文编号：2370426
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