新近纪软岩质水平滑带的结构与内部黏土矿物聚集规律  

The structure and distribution characteristic of clay minerals in bedding parallel to the shear zone of the Neogene soft rock

作　　者：辛鹏[1,2] 石菊松 胡乐 王涛 吴树仁[1,2] XIN Peng;SHI Jusong;HU Le;WANG Tao;WU Shuren(Institute of Geomechanics Chinese Academy of Geological Science Beijing,100081;Laboratory of Neotectonic Movement and Geohazard,of Ministry of Natural Resources,Beijing,100081;China Geological Environment Monitoring Institute,Beijing,100037;College of Earth Sciences and Resources,China University of Geosciences(Beijing),Beijing,100083)

机构地区：[1]中国地质科学院地质力学研究所,北京100081 [2]自然资源部新构造运动与地质灾害实验室,北京100081 [3]中国地质环境监测院,北京100037 [4]中国地质大学(北京)地球科学与资源学院,北京100083

出　　处：《地质学报》2020年第5期1625-1637,共13页Acta Geologica Sinica

基　　金：国家自然基金项目(编号41402281);中国地质调查局项目(编号DD20190717);中国地质科学院地质力学研究所科研项目(编号22)联合资助成果。

摘　　要：新近纪软岩质水平滑带控制了平推式滑坡的滑移过程,其内部黏土矿物的分布规律决定着滑坡能否出现低角度滑移。为分析水平滑带内黏土矿物的聚集规律,论文对典型地质剖面内物质组成、结构、黏土矿物含量与对应力学性质开展了定量测试,试验发现随着累积位移的增大,水平滑带的结构呈碎裂化、劈理化、塑性化、泥化渐进破坏状。滑带上边界的累积位移量最大,中部剪切面、下边界面处累积位移逐次递减。在同一滑带内,累积位移量越大的剪切面,其黏粒含量、含水率就越高。以簸箕山滑坡为例,上边界面、中部剪切面与下边界面的黏粒含量分别达到62.60%、62.46%、58.04%,含水率分别为28.82%、25.34%、25.52%。滑带的剪胀机制控制了上述水岩耦合作用过程。The movement of translational landslides was controlled by the bedding parallel to the shear zone in the Neogene soft rock,in which the distribution of clay minerals determined whether the landslide could slide along a low-angle zone.In order to analyze the aggregation law of clay minerals in bedding parallel shear zone,the composition,structure,clay mineral content and stress properties of six representative geological sections were quantitatively tested.It is found that the structure of bedding parallel to the shear zone shows fragmentation,cleavage,plasticization and mud.The cumulative displacement at the upper boundary of the shear zone is the largest,while the cumulative displacement at the middle and bottom boundary planes decreases gradually.The material composition,hydraulics,and mechanical properties of mudstones at the above three locations change synergistically.Taking Bojishan landslide as an example,the contents of clay particles on upper boundary,middle shear planes and bottom boundary are 62.60%,62.46%and 58.04%,respectively,and the water content is 28.82%,25.34%,25.52%.The dilatancy mechanism in shear zone controls the coupling process between water and soft rock.

关 键 词：新近纪 软岩 水平滑带 黏土矿物 聚集规律 

分 类 号：P642.22[天文地球—工程地质学]