含水率对西昌昔格达组粘土岩抗剪强度的影响研究  

Study on the influence of water content to shear strength of Xigeda-strata clay rock in Xichang

作　　者：张威[1] 徐则民[1] 刘文连 李丽[3] 

机构地区：[1]昆明理工大学,昆明650093 [2]中国有色金属工业昆明勘测设计研究院,昆明650011 [3]西南石油大学油气藏地质及开发工程国家重点实验室,成都610500

出　　处：《工程勘察》2011年第5期1-5,共5页Geotechnical Investigation & Surveying

基　　金：国家自然科学基金项目(40572159;40772189);教育部高等学校博士点基金(20060674009);云南联合基金重点项目(U1033601);交通部西部科技项目(200831876723)

摘　　要：昔格达组是西南地区第四纪的一套静水河湖相沉积地层,岩石矿物成分复杂,粘土岩具有遇水软化、强度随含水率升高而降低的特点。本文以西昌昔格达组粘土岩在不同含水率下的剪切试验为基础,从多角度就含水率对该区粘土岩抗剪强度的影响程度及影响机理进行了分析。试验发现,随着含水率的增加,粘土岩抗剪强度明显降低,含水率对粘土岩粘聚力及内摩擦角的影响具有明显的停滞性。粘土岩的SEM矿物形貌特征分析表明,在粘土岩片架结构中,抗剪强度主要由"团聚体"的三个强度分量共同产生,随着含水量的增加,各分量均呈下降趋势,最终导致"团聚体"破坏,使粘土岩抗剪强度降低。The Xigeda strata is a set of Quaternary Period’s still water river and lacustrine faces sediments in the Southwest China,and those rock mineral components are very complex.The clay rock is of the features： softening when encountering water and the strength reducing along with moisture content increasing.Based on the shearing tests for Xigeda-strata clay rock under different water contents,the influence of water content to the rock in Xichang and its influence mechanism are analyzed from different aspects.From the tests,it is found that the shear strength of the rock reduce obviously with the increasing of water content,and the influence of water content to the cohesion and the internal friction angle of clay rock is obvious stagnate under some conditions.From the analysis on SEM mineral appearance characteristics of the rock,it is indicated that in the piece frame structure of the rock,the shear strength mainly forms by the coacervate’s three strength components,and that with the increase of water content,all the components decrease which finally causes the coacervate failure and the reduce of shear strength.

关 键 词：昔格达组 粘土岩 含水率 抗剪强度 

分 类 号：TU458[建筑科学—岩土工程]