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通过对重庆小南海地震崩滑堆积体进行野外地质调查和工程地质勘察等相关工作,阐述了该崩滑堆积体的基本特征和形成机制,认为其形成过程经历了“风化剥蚀→震荡抛射→崩滑堆积→堵江成湖”4个阶段,其岩体破坏形式为高度破裂或严重高度破裂状态,其岩体破坏过程以崩塌为主,滑动为辅。研究发现,小南海地震崩滑堆积体的最终形成是受地震构造运动及应力、岩体构造、地形地貌及地震波作用等因素综合作用的结果:(1)该区NE向黔江逆滑(右行)断裂与NNW向仰头山逆滑(左行)断层形成的“X”型地震构造组合及轴向呈NWW向的构造压应力使小南海断块内部发生张滑(左行)破裂而导致61/4级地震发生;(2)该区呈“X”形展布的3组主要构造节理是崩滑体发育的物质基础,大、小垮岩在地震波作用下最终发生了向山体临空面(约145°~155°方向)的各自崩滑;(3)从崩滑堆积体中发现的灰岩块石证明崩滑体原始地层中曾含二叠系栖霞组和茅口组灰岩,这为恢复崩滑前山体地形提供了直接证据;(4)崩滑体中堆积岩块直径分布区域沿约150°方向自WN到ES依次递减,间接证明了地震时崩滑体抛洒方向为约150°方向,且大、小垮岩分别形成堆积区,交叉堆积部分较少。
The basic characteristics and formation mechanism of the collapse-slide accumulation body are described through field geological investigation and engineering geological investigation of the collapse and collapse of the Xiao Nanhai earthquake in Chongqing. The formation process of the collapse-slide accumulation body is experiencing that the formation process has experienced “weathering, erosion → oscillating ejection → Collapse collapse and accumulation → blocking the river into a lake, ”the four stages, the rock mass destruction form is highly ruptured or severely ruptured state, the rock mass destruction process to collapse, slip as supplements. It is found that the final formation of the collapse and collapse mass of the Xiaonanhai earthquake is a result of the combined action of seismic tectonic movement and stress, rock mass structure, topography, and seismic wave. (1) ) And the “X” -type seismic tectonic assemblage of upwelling (left bank) NNW uplift and the structural compressive stress in NWW direction resulted in the occurrence of zigzag (left bank) rupture in the Xiao Nanhai fault Which led to the occurrence of 61/4 earthquakes. (2) The three major structural joints distributed in the “X” shape in this area are the material basis for the development of landslides. The large and small-volume rock events eventually took place under seismic waves (3) the limestone blocks found in the landslide deposits show that the original formations in the landslides have ever existed in the Permian Qixia Formation and Mao (4) The distribution of the diameter of the accumulated rock mass in the collapse bodies decreases from WN to ES in the order of 150 °, which indirectly proves that the collapse of the landslide caused by the earthquake Body throwing direction is about 150 ° direction, and the large and small boulders formed a stacking area, respectively, with less cross-piling up.