降雨对山泉滑坡地下水渗流及滑坡稳定性的影响

发布时间：2018-03-21 22:29

  本文选题：降雨入渗　切入点：山泉滑坡　出处：《成都理工大学》2015年硕士论文　论文类型：学位论文

【摘要】：降雨是导致滑坡失稳的主要原因之一。降雨入渗会增大滑坡岩土体的重度,还会使滑坡体内水位抬升,增加饱和区孔隙水压力,降低非饱和区基质吸力,降低抗剪强度。因此,分析降雨入渗对山泉滑坡稳定性的影响具有重要意义。本文采用现场地质调查、定性分析与数值计算的方法,对不同降雨条件下山泉滑坡地下水流场变化进行了研究,并在此基础上,分析了降雨入渗对山泉滑坡稳定性的影响。主要的研究工作及所取得的认识如下:1.山泉滑坡平面形态呈挂钟形态,主滑方向145°,后缘宽度较大,向前缘方向宽度渐小。主滑方向最大纵长达310m,坡面平均长约280m,最大横宽约330m,平均宽约260m,面积约0.0838Km2,平均厚度约9.5m,滑坡体规模80万m3,为中型中层堆积层(土质)滑坡。2.山泉滑坡为典型的牵引式滑坡,其发生蠕滑变形的原因是前缘的人工开挖改变了原有的坡形条件,而降雨作用诱发了滑坡的变形破坏。3.研究了在不同降雨强度、不同降雨历时及一次强降雨全过程三种降雨条件下,山泉滑坡地下水流场变化规律。在降雨的初始阶段,雨水优先向山泉滑坡坡脚方向渗透,水位首先在坡脚处抬升。而降雨结束后,山泉滑坡坡脚处水位下降会出现延后现象。降雨强度和降雨持续时间的增加,会导致山泉滑坡地下水位上升。一次强降雨停止后,山泉滑坡地下水位变化总体趋势为:先下降较快,然后下降速率逐渐减缓。由于山泉滑坡下层碎块石土较厚,且渗透性较好,因此地下水比较容易接受降雨入渗补给,在雨停后地下水位及时下降。没有出现明显的滞后现象。4.对不同降雨条件下山泉滑坡的稳定性进行计算分析,获得了不同降雨条件下山泉滑坡的稳定性变化规律。在降雨强度较小(≤20mm/d)且降雨时间较短时,降雨对山泉滑坡稳定性影响小,随着降雨强度的增加,降雨对山泉滑坡稳定性的影响变大。在相同降雨强度(30mm/d)下,随着降雨持续时间的增长,山泉滑坡稳定性快速下降。暴雨会使山泉滑坡的稳定性下降到不稳定状态。雨停后,山泉滑坡稳定性约在两天时间内回升到基本稳定的状态。在此之后,山泉滑坡稳定性呈缓慢回升,逐渐趋于稳定。山泉滑坡在天然状态和较小的降雨强度(≤20mm/d)且降雨时间较短条件下,处于稳定状态。但在暴雨和持续的中等降雨强度条件下,山泉滑坡会进入不稳定状态。
[Abstract]:Rainfall is one of the main causes of landslide instability. Rainfall infiltration will increase the severity of landslide rock and soil mass, raise the water level of landslide, increase pore water pressure in saturated area, reduce the suction of matrix in unsaturated area, and reduce shear strength. It is of great significance to analyze the influence of rainfall infiltration on the stability of mountain spring landslide. In this paper, the variation of groundwater flow field of mountain spring landslide under different rainfall conditions is studied by means of field geological investigation, qualitative analysis and numerical calculation. On this basis, the influence of rainfall infiltration on the stability of mountain spring landslide is analyzed. The main research work and the understanding obtained are as follows: 1. The plane shape of mountain spring landslide is in the form of wall clock, the main slide direction is 145 掳, and the width of the rear edge is large. The width of the front edge direction is smaller. The maximum longitudinal length of the main slip direction is 310 m, the average slope surface length is about 280 m, the maximum transverse width is about 330 m, the average width is about 260 m, the area is about 0.0838 km ~ 2, the average thickness is about 9.5 m, and the landslide body is 800000 m ~ 3 in size, which is a medium middle layer (soil) landslide. Shanquan landslide is a typical traction landslide, The reason of creep deformation is that the artificial excavation of the leading edge changes the original slope condition, and rainfall induces the deformation and failure of landslide. 3. The different rainfall intensity is studied. Under three kinds of rainfall conditions: different rainfall duration and one heavy rainfall, the groundwater flow field of Shanquan landslide changes. In the initial stage of rainfall, Rain Water preferentially penetrates to the foot of mountain spring landslide. The water level rises first at the foot of the slope. After the rainfall ends, the drop of the water level at the foot of the mountain spring landslide will be delayed. The increase in the intensity and duration of the rainfall will lead to the rise of the underground water level of the mountain spring landslide. After a strong rainfall has stopped, The general trend of groundwater level change in Shanquan landslide is that the groundwater level decreases rapidly and then slows down gradually. Because the debris and rock soil in the lower layer of Shanquan landslide is thicker and the permeability is better, it is easy for groundwater to accept rainfall infiltration and recharge. The groundwater level drops in time after the rain stops. There is no obvious lag phenomenon .4.The stability of the mountain spring landslide under different rainfall conditions is calculated and analyzed. When the rainfall intensity is less than 20 mm / d and the rainfall time is short, the influence of rainfall on the stability of mountain spring landslide is small, and with the increase of rainfall intensity, the stability of mountain spring landslide under different rainfall conditions is obtained. Under the same rainfall intensity (30 mm / d), with the increase of rainfall duration, the stability of mountain spring landslide decreases rapidly. After the rain stops, the stability of mountain spring landslide decreases to an unstable state. The stability of the mountain spring landslide returned to a basically stable state in about two days. After that, the stability of the mountain spring landslide rose slowly. The landslide is in a stable state under the condition of natural condition and smaller rainfall intensity (鈮，

本文编号：1645867