摘要
以金沙江乌东德水电站右岸的鸡冠山梁子高陡斜坡为典型实例,在斜坡表层地震动监测基础上,通过在斜坡弹性模型底部分别输入水平、竖向Ricker子波,发现:斜坡顶部低模量岩体材料在水平Rick子波激励下,易产生放大效应;而当输入竖向Rick子波时,易在模型表层地形凸起部位产生共振放大,其顶面表层卓越频率也与现场实测值基本一致。其次,对比分析了在分别输入汶川八角什邡加速度记录、典型鲁甸地震加速度记录时的斜坡弹塑性模型的稳定性和动力响应特征,发现:(1)斜坡在静力条件下可能存在3种不同位置潜在滑面,但输入两种地震波后,变形破坏区仅发生在顶部滑面位置;(2)输入汶川地震波时,斜坡顶部滑面剪应变增量明显大于输入鲁甸地震波时对应值,且前者的滑面出现明显整体拉破坏区,滑面上部水平、竖向残余变形也不收敛,处于震后斜坡失稳状态。后者滑面底部无明显的拉破坏区,滑面上部残余变形收敛,处于震后斜坡稳定状态;(3)斜坡水平、竖向加速度都在斜坡顶部低模量材料表层出现明显的放大现象,场地效应明显。此外,表层加速度普遍大于斜坡内部相应值,尤其是地形凸起位置。输入汶川地震波时斜坡顶部水平向加速度放大系数大于鲁甸地震波相应值,但竖向加速度放大系数两者基本一致。
The Jiguanshanliangzi high-steep slope is taken as a typical case study in Wudongde hydropower station near Chin-sha River. Based on seismic monitoring of the slope surface, firstly, after inputting horizontal and vertical Ricker wavelets at the elastic slope model bottom, it is found that the low modulus of rock mass materials at the slope top is easily amplified after the excitation of the horizontal Rick wavelet. The surface convex topography is easy to produce resonance amplification when the vertical Rick wavelet is excited. The predominant frequencies of the top surface are consistent with the measured values. Secondly, comparative analysis of the slope stability and dynamic response characteristics are performed when inputting the real Wenchuan and Ludian earthquake acceleration records. It can be found that the slope may have three different potential slip surfaces at different locations under the static condition. However, when inputting the above two seismic waves, the deformation and failure occur only at the slope top position. When inputting the Wenchuan seismic wave, the shear strain increment of the top slip surface is significantly greater than that when inputting Ludian seismic wave. The tension failure zone is observed at the slip surface and the horizontal and vertical residual deformation is not convergence. The slope is at the state of instability after the earthquake. When inputting the Ludian seismic wave, there is no tensile failure zone observed at the slip surface and the residual deformation is convergence, which means that the slope is stable after the earthquake. The slope of horizontal and vertical acceleration at the slope top surface appears significantly enlargement due to a low modulus material, showing obvious site effect. In addition, the surface acceleration is generally greater than the corresponding values within the slope, especially at the location of convex topography. The amplification factor of horizontal acceleration at the slope top after inputting the Wenchuan seismi
作者
王文沛
李滨
冯振
张博文
高杨
WANG Wen-pei;LI Bin;FENG Zhen;ZHANG Bo-wen;GAO Yang(China Institute of Geological Environment Monitoring,Beijing 100081,China;Institute of Geomechanics,Chinese Academy of Geological Sciences, Beijing 100081,China;School of Engineering and Technology,China University of Geosciences,Beijing 100083,China)
出处
《岩土力学》
EI
CAS
CSCD
北大核心
2019年第1期297-304,314,共9页
Rock and Soil Mechanics
基金
国家自然科学基金项目(No.41502305)
企业合作项目(No.WDD0385)~~
关键词
场地效应
失稳机制
高陡斜坡
放大系数
site effect
failure mechanism
high-steep slope
amplification factor
