汶川震中岩浆岩高边坡破坏模式与崩塌机理  

Collapse Mode and Mechanism of High Magmatite Rock Slope in Wenchuan Epicentral Area

作　　者：胡新丽[1] 唐辉明[1] 朱丽霞[1] 

机构地区：[1]中国地质大学工程学院,湖北武汉430074

出　　处：《地球科学（中国地质大学学报）》2011年第6期1149-1154,共6页Earth Science-Journal of China University of Geosciences

基　　金：国家自然科学基金项目(No.40872175);国家重点基础研究发展计划"973"课题(No.2011CB710604);中国地质调查局项目(No.1212010914036)

摘　　要：汶川8.0级大地震触发了大量岩石边坡崩塌次生地质灾害,不同岩性及结构的岩质高边坡,强震作用下的破坏机理不同,震中映秀岩浆岩高边坡在强震中破坏严重,因此急需开展其破坏机理的研究.以震中映秀典型高边坡崩塌-虎嘴崩塌为研究对象,在工程地质条件研究的基础上,采用结构面统计模拟方法,深入分析岩浆岩边坡的结构面组合特征,通过赤平投影法初步确定了该类边坡的破坏模式:由3组主控结构面相互贯通的双平面滑动.恢复老虎嘴岩质边坡在地震前的原始坡形,采用2DUDEC再现地震作用下老虎嘴岩质高边坡的破坏过程,得出在地震作用下的破坏规律:老虎嘴边坡在地震作用下的渐进破坏过程主要表现为边坡前缘岩体首先破坏,坡顶岩体沿着3组结构面的切割贯通面也产生拉裂破坏发生崩塌,最终整个边坡溃塌.在重力和地震的双重作用下坡顶破坏呈现出抛射状.Wenchuan earthquake of magnitude of 8.0 triggered a large amount of rock slope collapse.In Yingxiu,many high magmatite rock slopes collapsed when Wenchuan earthquake struck,which resulted in huge damage.So it is urgent to study the collapse mechanism.This study takes Laohuzui collapse,a typical high slope collapse located at Yingxiu,the Wenchuan earthquake epicenter,as the object of this research.The engineering geological condition was investigated and the physical and mechanical parameters of rockmass and structural plane was determined.With the stereographic projection method using the discontinuity network simulation results,the basic failure modes of the slope was obtained,which is dual-plane sliding mainly due to the interconnected three group joints.Re-establishing the Laohuzui high slope model before earthquake,the process of dynamic response on the rock slope under earthquake was simulated by using 2DUDEC,and the destruction and collapse mechanism was analyzed.The main conclusion is that the Laohuzui slope collapse is a progressive failure.At first,the tensile failure took place in the slope toe,then the slope top would be subject to tensile failure followed by the front surface failure along the cut-through plane by three group joints,which resulted in the whole slope collapse.The slinging failure took place at the slope top under the seismic and gravity action condition.

关 键 词：汶川地震 岩浆岩高边坡 崩塌破坏机理 离散单元法 工程地质 

分 类 号：P642[天文地球—工程地质学]