摘要
重庆市巫山县望霞危岩是长江三峡黄金水道巫山段左岸的一处典型重大危岩体,2010年雨季出现明显变形,随后转入应急监测,并依据监测成果两次成功预警。本文基于地质分析和监测成果,研究望霞W2-2危岩体变形-演化的动力学过程,发现持续降雨是崩滑灾害发生的直接诱发因素。雨水渗入浸泡使泥岩软基强度降低,塑流变形加剧,加大了危岩的下部变形程度,使上覆砂岩层沿接触底面出现拉裂。同时水体作用造成危岩中节理、裂隙极其发育。W2-2危岩体变形破坏演化过程可分为前期累积变形、匀速变形、加速变形和临界加速变形四个阶段,其中加速变形点和临界加速变形点具有很好的预警指示意义,加速点可视为岩体稳定与不稳定破坏的分界点。
The Wangxia rock body（W2-2）is a dangerous body of rock located on the left side of the Three-Gorges section of the Yangze River in Wushan county.It suffered evident deformation during the monsoon of 2010;emergency monitoring was immediately conducted and two forecasts were made successfully.The evolution of W2-2is similar to that of other common dangerous rock bodies.In this study,geological investigations and in-situ monitoring are used to determine the dynamic processes involved in the deformation-evolution of W2-2.Results show that,in general,falling of sliding masses into the river was induced by continued rainfall,and that infiltrated rainwater weakened the intensity of the soft mudstone foundation.The plastic flow was thus strengthened,and bottom deformation of the rock body occurred.As a result,tensile cracks were generated in the overlying sandstone layer.In addition,a fracture was widely developed in the rock body because of the effect of river water.Ultimately,rainfall occurring during the period from October 10 to 15,2011 led to integral collapse of the W2-2on October 21.Evolution of the deformation and failure of W2-2included four stages：initial cumulative deformation,uniform deformation,accelerating deformation,and threshold-accelerated deformation.The accelerating point and the threshold-accelerated point are thus considered to be effective indicators for use in forecasting,and the accelerating point is identified to be representing the threshold between the stability and instability of the rock body.
出处
《地震工程学报》
CSCD
北大核心
2015年第4期1066-1072,共7页
China Earthquake Engineering Journal
基金
中国地质调查局地质调查工作项目(1212011220164)
国家自然科学基金项目(41402322)
关键词
危岩
变形监测
降雨
演化过程
dangerous rockmass
deformation monitoring
rainfall
evolution process
