【摘要】：我國是一個地質(zhì)災(zāi)害多發(fā)的國家,其中邊坡災(zāi)害占到了很大比例。進入新世紀以后,我國經(jīng)濟持續(xù)高增長,各地工程建設(shè)的增多,導(dǎo)致地質(zhì)災(zāi)害呈有增無減的趨勢。而在誘發(fā)邊坡滑坡的眾多因素中,降雨尤其是強降雨是誘發(fā)邊坡失穩(wěn)破壞這一地質(zhì)災(zāi)害的最重要因素。入滲過程改變了坡體內(nèi)部含水率,導(dǎo)致土壓力、孔隙水壓力等發(fā)生變化,使土體抗剪強度降低,邊坡穩(wěn)定性下降。論文主要研究內(nèi)容如下:(1)設(shè)計降雨入滲模型試驗,在不同監(jiān)測點布設(shè)處、不同降雨時間等條件下,通過對坡體內(nèi)部含水率、孔隙水壓力、土壓力等的變化情況進行分析,得到邊坡降雨入滲規(guī)律。選用光纖光柵傳感器和多通道光纖光柵解調(diào)儀設(shè)計了一套監(jiān)測系統(tǒng),并應(yīng)用到了邊坡降雨入滲模型試驗之中。在LabVIEW開發(fā)環(huán)境下,開發(fā)了一套監(jiān)測軟件,實現(xiàn)了對試驗數(shù)據(jù)的采集和處理。(2)試驗數(shù)據(jù)表明,降雨入滲過程中,由于降雨入滲量與泥沙侵蝕量的相對關(guān)系,坡體內(nèi)部土壓力會有一個先減小再增大的過程。且降雨結(jié)束后,坡體內(nèi)部的應(yīng)力值均比初始應(yīng)力大。而孔隙水壓力在降雨入滲過程中,開始無明顯變化,隨著入滲的進行,其值逐漸增大。之后坡頂土體由非飽和趨于飽和,且隨著飽和區(qū)的向下擴張,坡頂下方區(qū)域含水率不斷增大,直至達到飽和狀態(tài)。試驗數(shù)據(jù)表明,在無任何護坡措施的情況下,坡頂位移變形較大,應(yīng)重點關(guān)注。(3)以邊坡降雨入滲模型試驗為背景,通過有限元數(shù)值模擬軟件PLAXIS,采用考慮基質(zhì)吸力和不考慮基質(zhì)吸力兩種方法,模擬了邊坡降雨入滲過程。并從初始孔壓場、不同降雨時刻邊坡滲流場、孔壓場等方面對比分析了以上兩種模擬方法的差異,將模擬結(jié)果與模型試驗數(shù)據(jù)進行對比,最后得出了對于不存在地下水的模型邊坡而言,采用不考慮吸力的模擬方法得到的結(jié)果更為符合實際的結(jié)論。
[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.
【學(xué)位授予單位】：中國地質(zhì)大學(xué)(北京)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TU411
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本文編號：2370426