降雨入渗条件下边坡稳定性数值分析

发布时间：2018-09-03 14:21

【摘要】：我国西南地区降雨量大,持时久,该地区的自然边坡和人工边坡在雨季经常发生滑坡,对人类生命、财产安全造成了巨大威胁。因此,降雨入渗条件下边坡的稳定性研究,具有一定的理论和实践意义。以云南省某一公路边坡为研究对象,根据研究区域的工程地质概况结合现场调研和室内试验,采用有限差分软件FLAC2D建立了边坡的数值模型,分析了不同的降雨强度、持时以及雨型对边坡稳定性的影响,并研究了锚杆支护对不同降雨雨型条件下边坡的加固作用。研究结果表明：降雨强度较大时,雨水入渗主要引起边坡表层的饱和度增加；而降雨强度较小时,雨水更容易入渗到边坡的内部。降雨持时相同时,边坡的剪应变增量和塑性区随着降雨强度的增大而增大；降雨条件下,边坡的破坏以剪破坏为主,同时在坡顶部位存在着一定范围的拉破坏区；降雨过程中,边坡的潜在滑移面由岩土层接触面处逐渐向坡顶部位延伸。强降雨条件下,边坡的位移较大,其中边坡水平向位移随着高程的减小而增大,而竖直向位移随着高程的减小而减小。随着降雨持时的增加,边坡的位移不断增大,而安全系数不断减小。不同降雨雨型下,雨强增加的情况下第一级边坡的饱和区最大,其次为雨强不变以及雨强减小的情况。锚固前相同高程处,雨强减小的情况下,坡面监测点的位移最大,雨强不变及雨强增加情况下位移依次减小。锚固后边坡的安全系数增大,坡面监测点的位移明显减小；不同降雨条件下锚固后边坡监测点位移关系与锚固前恰好相反。降雨作用后锚杆的轴力和剪力均增大,不同降雨条件下,锚杆相同部位的轴力和剪力均相近。
[Abstract]:The rainfall in southwest China is large and lasting for a long time. The natural and artificial slopes in this area often slide in the rainy season, which poses a great threat to human life and property safety. Therefore, the study of slope stability under rainfall infiltration is of theoretical and practical significance. Taking a highway slope in Yunnan Province as the research object, the numerical model of the slope is established by using the finite difference software FLAC2D, and the different rainfall intensity is analyzed according to the engineering geological situation of the studied area combined with the field investigation and indoor test. The influence of duration and rain type on slope stability is studied. The reinforcement effect of bolt support on slope under different rainfall rain patterns is studied. The results show that Rain Water infiltration mainly results in the increase of surface saturation of slope when rainfall intensity is high, while when rainfall intensity is small, Rain Water infiltration is more easily to the slope interior. When the rainfall duration is the same, the increment of shear strain and plastic zone of slope increase with the increase of rainfall intensity. Under rainfall condition, the failure of slope is dominated by shear failure, and at the same time there is a certain range of tensile failure zone at the top of the slope. The potential slip surface of the slope extends gradually from the contact surface of the rock and soil layer to the top of the slope. Under the condition of heavy rainfall, the displacement of the slope is larger, in which the horizontal displacement of the slope increases with the decrease of the elevation, while the vertical displacement decreases with the decrease of the elevation. With the increase of rainfall duration, the slope displacement increases and the safety factor decreases. Under different rainfall patterns, the saturation zone of the first grade slope is the largest when the rainfall intensity is increasing, and the rain intensity is invariant and the rain intensity decreases. At the same height before anchoring, the displacement of the monitoring point on the slope is the largest when the rain intensity decreases, and the displacement decreases in turn when the rain intensity is constant and the rain intensity is increasing. After anchoring, the safety factor of the slope increases and the displacement of the slope surface monitoring point decreases obviously, and the displacement relationship of the slope monitoring point after anchoring under different rainfall conditions is opposite to that before anchoring. The axial force and shear force of anchor rod increase after rainfall, and the axial force and shear force of the same part of anchor rod are similar under different rainfall conditions.
【学位授予单位】：兰州大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TU43

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