發(fā)布時間：2018-06-10 19:21

  本文選題：灌溉型黃土滑坡 + 形成機理�。� 參考：《長安大學》2015年碩士論文

【摘要】：黃土滑坡是黃土地區(qū)一種比較特殊的地質災害,因其頻發(fā)性、廣布性、復雜性、災難性等特點,嚴重威脅著人民生命財產(chǎn)和水電交通等工農業(yè)設施的安全。涇陽南塬自1976年引水灌溉以來,由于長期的漫灌導致塬區(qū)地下水位不斷抬升,改變了塬區(qū)水文地質條件,致使黃土滑坡頻繁發(fā)生,給人民的生命和財產(chǎn)帶來了巨大的損失,同時嚴重影響地區(qū)社會經(jīng)濟的發(fā)展。本文以涇陽南塬河灘村典型黃土滑坡為例,通過野外實際調查、測量、勘探和室內實驗等,分析研究了灌溉型黃土滑坡的發(fā)育特征、形成機理及致災機理。主要研究內容如下:(1)通過現(xiàn)場實際調查,獲得了研究區(qū)孕災條件,主要包括:地形地貌、地質構造、水文氣象條件及水文地質條件。通過室內試驗,對黃土的顆粒組成、物理力學性質和結構特性進行了研究,就高陡后壁、后緣裂縫和落水洞等的形成進行了詳細分析。(2)對河灘村黃土滑坡的發(fā)育特征進行了詳細的調查,河灘村黃土滑坡較發(fā)育,主要具有如下特征:滑動突然、啟程高速,滑動距離遠,災害嚴重,滑體多以塊體方式運動、表面呈波浪狀等特征。(3)河灘村黃土滑坡均為高速遠程黃土滑坡,主要是由灌溉誘發(fā)。認為研究區(qū)灌溉型黃土滑坡主要經(jīng)歷3個階段:蠕動—拉裂階段→輕微液化—滑動階段→嚴重液化—劇滑階段。分析了蔣劉滑坡群演化機制,由于前次滑動改變了后緣地質條件,加之后緣拉張裂縫為灌溉水提供了良好的入滲通道,塬區(qū)滑坡頻發(fā),且具有演化的特點。(4)采用FLAC3D有限差分軟件對西河灘黃土滑坡進行了數(shù)值模擬,研究了由于灌溉引起地下水位上升對坡體的影響。發(fā)現(xiàn)最大剪應力出現(xiàn)在飽和黃土層內,剪切破壞發(fā)生時土體在豎向有相對位移,塬面產(chǎn)生了拉裂縫,坡腳附近有隆起現(xiàn)象,坡體發(fā)生剪切破壞的塑性區(qū)呈圓弧形條帶狀區(qū)域,當整個塑性區(qū)在黃土層中貫通,坡體就從飽和黃土層剪出,最終導致斜坡失穩(wěn)破壞�；嫘螤詈图舫隹谖恢门c實際相符,采用數(shù)值模擬較直觀地分析了地下水位抬升對坡體的影響。
[Abstract]:Loess landslide is a special geological hazard in loess area. Because of its frequent, widespread, complex and disastrous characteristics, it seriously threatens the safety of industrial and agricultural facilities such as people's life, property and hydropower transportation. Since the diversion irrigation in 1976, the groundwater level has been rising continuously because of the long-term flood irrigation, which has changed the hydrogeological conditions, caused the loess landslide to occur frequently, and brought huge losses to the lives and property of the people. At the same time seriously affect the socio-economic development of the region. Taking typical loess landslide in Hetan village as an example, through field investigation, survey, exploration and laboratory experiments, this paper analyzes and studies the developmental characteristics, formation mechanism and disaster-causing mechanism of irrigated loess landslide. The main research contents are as follows: (1) based on the field investigation, the disaster preparedness conditions in the study area are obtained, including topography, geological structure, hydro-meteorological conditions and hydrogeological conditions. Through laboratory tests, the particle composition, physical and mechanical properties and structural characteristics of loess were studied. The development characteristics of loess landslide in Hetan Village are investigated in detail. The loess landslide in Hetan Village is relatively developed and has the following characteristics: sliding suddenly, setting off at high speed. The sliding distance is long, the disaster is serious, the sliding body moves in block way, the surface is wavy and so on.) Loess landslide in Hetan Village is high speed and long distance loess landslide, which is mainly induced by irrigation. It is considered that the irrigated loess landslide in the study area mainly goes through three stages: creeping-pulling crack stage and slight liquefaction-sliding stage and severe liquefaction-hyper-slip stage. The evolution mechanism of Jiangliu landslide group is analyzed. Because the previous slide changed the geological condition of the rear edge and the extension crack of the rear edge provided a good infiltration channel for irrigation water, the landslide occurred frequently in the tableland. The characteristics of evolution. (4) numerical simulation of loess landslide in Xihetan is carried out by using FLAC3D finite difference software, and the influence of the rise of groundwater level caused by irrigation on slope body is studied. It is found that the maximum shear stress occurs in the saturated loess layer, the soil has relative displacement in the vertical direction when the shear failure occurs, the tensile cracks occur on the plateau surface, the uplift phenomenon occurs near the slope foot, and the plastic zone of the shear failure of the slope body takes on a circular arc strip zone. When the whole plastic zone is connected in the loess layer, the slope body is cut out from the saturated loess layer, which leads to the failure of slope stability. The shape of the sliding surface and the location of the shear outlet are consistent with the actual situation. The influence of the uplift of the groundwater level on the slope body is analyzed intuitively by numerical simulation.
【學位授予單位】：長安大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TU444;P642.22

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