堆积层斜坡地震动地形效应试验研究  

Experimental research of the topographic effects of slopes in earthquake

作　　者：黄栋[1,2] 乔建平[1,2] 张小刚[1,2] 陈宇龙[3] HUANG Dong QIAO Jianping ZHANG Xiaogang CHEN Yulong(Key Laboratory of Mountain Hazards and Surface Process, Chinese Academy of Sciences, Chengdu, Sichuan 610041, China Institute of Mountain and Environment, Chinese Academy of Science and Ministry of Water Conservancy,. Chengdu, Siehuan 610041, China Department of Civil Engineering, University of Tokyo, Tokyo 113- 8656, Japan)

机构地区：[1]中国科学院山地灾害与地表过程重点实验室,四川成都610041 [2]中国科学院水利部成都山地灾害与环境研究所,四川成都610041 [3]东京大学土木工程系

出　　处：《岩石力学与工程学报》2017年第3期587-598,共12页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家自然科学基金资助项目(41301009;41471429);中国科学院STS项目(KFJ-EW-STS–094)~~

摘　　要：地震中已经观测到斜坡的地震响应会受地形的影响。因此,在划分堆积层斜坡坡面类型的基础上,开展不同坡形振动台模型试验。试验结果表明:输入强度较强的地震波时,斜坡表面加速度响应峰值放大系数大于斜坡内部,且斜坡中上部及表面曲率变化较大处(AC2)加速度放大效应更为显著。坡形的变化影响着斜坡自振频率,表现为上凸下凹型斜坡的自振频率接近于5 Hz,其他坡形斜坡接近于10 Hz。模型破坏的临界加速度阈值为500~700 Gal与斜坡稳定性计算结果基本一致。坡形影响斜坡的滑动面位置及厚度,曲率半径越大(凸型为正、凹型为负)的坡形滑动面厚度越大。滑动距离(与坡脚的距离)量测显示:直线型和上凹下凸型斜坡滑动距离最远危害范围大,凸型和上凸下凹型斜坡运动距离较远危害范围较大,凹型坡运动距离较近危害范围较小。因此,直线型和上凹下凸型斜坡的危险性(危害性)最高,凸型和上凸下凹型斜坡危险性较高,凹坡危险性最低。本研究的意义在于加强地震力作用下地形效应对斜坡稳定性研究的认识,为防灾减灾和灾害风险评价提供科学依据。It has been observed that during an earthquake, the seismic response of slopes could be affected by the topography. Therefore, a general earthquake-induced slope model is defined and designed with five different slope shapes based on the statistical relations between the earthquake-induced landslides and the slope shapes. According to the test results, the amplification factor of the peak ground acceleration（PGA） on the surface of the slope was higher than that in the slope when the intensity of the input motion was relatively high. The site at the upper of the slope with the largest curvature on the middle of the slope surface（AC2） had the most notable amplification effect. The shape of the slope affected the natural frequency of the ground for the slope. The upper convex and lower concave slope had a natural frequency close to 5 Hz while the slopes of other shapes had a natural frequency close to 10 Hz. The critical acceleration values at failure ranged from 500 to 700 Gal, which were consistent with the calculated values for the slope from material strength tests. The shape of the slope affects the location and depth of its failure surface. The slope with large curvature radius（positive for convex and negative for concave） usually has a deeper sliding failure surface. The concave slopes have a shorter sliding distance and a smaller hazardous range. The convex and the upper convex and lower concave slopes have a longer sliding distance and a larger hazardous range. The linear and the upper concave and lower convex slopes have the longest sliding distance and the largest hazardous range. Therefore, the slopes with the linear or the upper concave and lower convex configurations have the highest risks, followed by the convex and the upper convex and lower concave slopes, while the concave slopes have a relatively strong ability to resist the ground motions and pose the lowest danger.

关 键 词：边坡工程 地形效应 振动台模型试验 动力响应 加速度响应峰值 

分 类 号：P642[天文地球—工程地质学]