本文關(guān)鍵詞：不同降雨條件下吾隘滑坡穩(wěn)定性分析　出處：《成都理工大學》2016年碩士論文　論文類型：學位論文

  更多相關(guān)文章： 吾隘滑坡 降雨 穩(wěn)定性分析 現(xiàn)場試驗

【摘要】：吾隘滑坡位于廣西南丹縣吾隘鎮(zhèn),其所在地區(qū)位于云貴高原向桂西北丘陵過渡的斜坡地帶,山地丘陵地貌分布廣泛,斜坡表面廣泛覆蓋著殘坡積土。桂西北是廣西滑坡頻發(fā)的地區(qū),其主要發(fā)生在連續(xù)陰雨、暴雨的時段。而針對南丹縣地區(qū)降雨型滑坡的相關(guān)研究較少,因此,通過對吾隘滑坡的研究,既可以排除其對周邊群眾的安全威脅,還可以為其所在區(qū)類似滑坡穩(wěn)定性分析提供參考。本文以吾隘滑坡為研究對象,進行了野外踏勘以及鉆探;查明了滑坡的邊界、形態(tài)及規(guī)模特征、滑坡體結(jié)構(gòu)特征及其變形特征;進行了現(xiàn)場試驗研究以及室內(nèi)試驗分析;對滑坡的變形演化機制及變形破壞模式進行了分析;運用極限平衡法及有限差分法,對在降雨條件下的吾隘滑坡進行穩(wěn)定性分析以及應(yīng)力應(yīng)變分析。主要結(jié)論和認識如下:(1)現(xiàn)場勘查表明:吾隘滑坡地處低山溝谷地貌,坡度較陡,存在兩處較明顯的滑塌,且在滑坡中后緣有明顯的拉張裂縫。(2)通過鉆探,查明了滑坡的地層以及物質(zhì)組成。進行了原位雙環(huán)試驗,測得了滑體土的滲透性,屬于中等透水。而下伏基巖為弱透水的砂質(zhì)泥巖,其起到相對隔水的作用,這有利于地下水在滑體內(nèi)富集,這對滑坡穩(wěn)定性不利。(3)針對當?shù)貧夂驐l件,考慮了不同降雨條件,對吾隘滑坡地下水與負孔隙水壓力進行了分析,得出:(1)降雨強度越大,相同時間內(nèi)滑坡體地下水位上升越快,負孔隙水壓力減小的越快,負孔隙水壓力等值線彎曲程度越大;(2)同一降雨強度下,隨著降雨歷時增大,滑坡體的負孔隙水壓力逐漸小,地下水位逐漸抬升;(3)在相同總降雨量下,雨強小、歷時長的降雨,更加充分地滲透到滑坡體內(nèi);而雨強大、歷時短的降雨,在靠近坡體表面形成暫態(tài)飽和區(qū),降雨不能充分入滲坡體;(4)降雨停止后,滲入滑坡體的雨水以及地表積水還在向坡體內(nèi)運移,在一定時間內(nèi),地下水位還會緩慢抬升,坡體內(nèi)的負孔隙水壓力也會逐漸減小,之后,隨著地下水的排泄,坡體內(nèi)的地下水會緩慢恢復(fù)到初始狀態(tài)。(4)基于非飽和土力學理論,對不同降雨條件下滑坡穩(wěn)定性進行了分析,得出:(1)48小時內(nèi),雨強越大,滑坡體穩(wěn)定性系數(shù)降幅越大,下降速率也越快;(2)隨著降雨歷時的延長,滑坡體的穩(wěn)定性系數(shù)逐漸減小,達到一定時間后,滑坡體處于欠穩(wěn)定的狀態(tài);(3)相同總降雨量下,雨強小、歷時長的降雨對滑坡體穩(wěn)定性更加不利;(4)在降雨期間和降雨停止后一天內(nèi),吾隘滑坡的穩(wěn)定性系數(shù)呈遞減的趨勢。降雨停止后一天時,滑坡處于欠穩(wěn)定狀態(tài)。降雨停止3天后,吾隘滑坡的穩(wěn)定性系數(shù)緩慢回升。(5)考慮了天然狀態(tài)及降雨條件,對吾隘滑坡的變形與穩(wěn)定性進行了數(shù)值模擬研究,得出:在天然狀態(tài)下,吾隘滑坡處于基本穩(wěn)定的狀態(tài),降雨條件下發(fā)生緩慢滑動,拉動后緣變形,并擠壓前緣,這與現(xiàn)場調(diào)查情況有較好的一致性。
[Abstract]:Wu AI landslide is located in Guangxi County of Nandan Wu AI Town, the area is located in the Yunnan Guizhou Plateau to the northwest of Guangxi hilly slope transition zone, hilly landforms are widely distributed, the slope surface widely covered with residual soil. In the northwest of Guangxi Guangxi landslide prone areas, which mainly occurred in the continuous rain, rain and for hours. Less relevant research, rainfall area of Nandan County landslide therefore, through the study of landslide of Wu AI, which can eliminate the surrounding masses of security threats, can also provide reference for similar area analysis of landslide stability in this paper. The Wu AI landslide as the research object, the field exploration and drilling; landslide the boundary to identify the morphology and size characteristics, structure characteristics and deformation characteristics of the landslide are analyzed; field tests and laboratory tests; the failure modes of deformation and deformation mechanism of Landslide Evolution Are analyzed; by using limit equilibrium method and finite difference method, the under rainfall Wu AI landslide stability analysis and stress strain analysis. The main conclusions are as follows: (1) the scene showed that Wu AI landslide is located in low mountain valley landform, a steep slope, there are two obvious the collapse and landslide in the trailing edge has obvious tensile cracks. (2) identified by drilling, landslide formation and material composition. The in situ loop test, permeability test with landslide soil, which is of medium grade. The bedrock is a low permeability of sandy mudstone, the play the relative water resisting effect, which is conducive to the enrichment of groundwater in the slide body, which is detrimental to the landslide stability. (3) according to the local climate conditions, taking into account the different rainfall conditions of Wu AI landslide groundwater and negative pore water pressure were analyzed, concluded: (1) the greater intensity of rainfall at the same In the landslide groundwater level rise faster, the faster the negative pore water pressure decreases, the bending degree of negative pore water pressure contour more; (2) the same rainfall intensity, with rainfall increasing, the negative pore water pressure of the landslide gradually small, underground water level rising; (3) in the same the total rainfall, rainfall intensity, rainfall duration, more fully penetrate into the landslide body; and the rain strong, short duration of rainfall, the formation of transient saturated zone near the slope surface, rainfall is not fully infiltration slope; (4) after the stop of rainfall infiltration sliding slope rainfall and surface water also to the slope movement, in a certain period of time, the groundwater level will slowly rise, after the negative pore water pressure in the slope will gradually decrease, and with the groundwater discharge, slope groundwater will slowly return to the initial state. (4) based on the theory of unsaturated soil mechanics, the different Under the condition of rainfall on landslide stability is analyzed, concluded that: (1) within 48 hours, the greater the rainfall intensity, slope stability coefficient the greater the decline, decline rate is faster; (2) with the rainfall duration, the stability coefficient of landslide decreases gradually, reached after a certain time, the landslide is unstable the state; (3) the same total rainfall, rainfall intensity, rainfall duration on landslide stability is more unfavorable; (4) in the rain and after one day, the stability coefficient of landslide presenting Wu AI decreased. One day after the rain stopped, the landslide is in an unstable state. The rain stopped after 3 days, the stability coefficient of landslide Wu AI slowly recovered. (5) considering the natural state and rainfall conditions, the deformation and stability of Wu AI landslide were studied by numerical simulation, obtained under natural state, Wu AI landslide is in stable state, the condition of rainfall There is a slow sliding, pulling the back edge deformation and pressing the front edge, which is in good agreement with the field investigation.

【學位授予單位】：成都理工大學
【學位級別】：碩士
【學位授予年份】：2016
【分類號】：P642.22

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