基于GDEM的坡脚劣化条件下三峡库区砂岩反倾岩质边坡的破坏机制研究  

Failure Mechanism of Sandstone Anticline Rock Slope in the Three Gorges Reservoir Area Under Slope Toe Deterioration by Using GDEM Software

作　　者：徐建城 江巍 齐志宇[2] 王金祥 XU Jiancheng;JIANG Wei;QI Zhiyu;WANG Jinxiang(Institute of Engineering Mechanics,China Earthquake Administration,Harbin 150080;Key Laboratory of Geological Hazards in Three Gorges Reservoir Area,Ministry of Education,Yichang 443002)

机构地区：[1]中国地震局工程力学研究所,哈尔滨150080 [2]三峡库区地质灾害教育部重点实验室,湖北宜昌443002

出　　处：《土工基础》2023年第3期448-454,共7页Soil Engineering and Foundation

基　　金：中国地震局工程力学研究所基本科研业务费专项资助项目(编号:2019D07);国家自然科学基金项目(编号:52079070)。

摘　　要：三峡库区反倾岩质边坡的坡脚岩体在水-岩作用下,物理力学性质易发生劣化,威胁边坡稳定。准确认识坡脚岩体劣化条件下反倾岩质边坡的破坏机制尤为重要。以三峡库区砂岩反倾岩质边坡为研究对象,利用GDEM数值软件建立了不同坡角、岩层倾角、层厚的边坡模型。对于坡脚劣化前后均未发生倾倒变形的边坡,分析了坡脚劣化前后边坡最大主应力的变化;对于坡脚劣化前稳定、坡脚劣化后发生倾倒变形的边坡,概述了反倾边坡在坡脚劣化条件下的变形演化过程,明确其对坡脚劣化的响应特征。另外,分析了坡角、倾角、层厚对边坡变形的影响,探明了砂岩反倾边坡破裂面的形态、位置特征,砂岩边坡主破裂面与层面夹角呈20~26°,以坡脚劣化岩体与上部变形岩体为界,破裂面自分界点向上成近直线形。砂岩反倾边坡中主要呈剥落-倾倒-折断式的破坏模式。Under the combined action of water-rock,the physical and mechanical properties of the rock mass at the toe of a anticline rock slope in the Three Gorges Reservoir area are prone to deteriorate,which might affect the stability of the slope.It is particularly important to accurately understand the failure mechanism of the anticline rock slope under the condition of deterioration of the rock mass at the toe of slope.In this paper,the sandstone anticline rock slope in the Three Gorges Reservoir area is presented as a case history.The slope models with different slope angle,rock dip angle and layer thickness are established by using GDEM numerical analysis software.For slopes without toppling deformation before and after toe deterioration,the variation of the maximum principal stress before and after toe deterioration is analyzed.For slopes that are stable before slope deterioration and have toppling deformation after slope deterioration,the deformation evolution process of anticline slope under the condition of the slope deterioration is summarized.Its response characteristics to the slope deterioration are clarified.In addition,the influence of the slope angle,dip angle and layer thickness on the slope deformation is analyzed,and the shape and location characteristics of the fracture surface of the sandstone anticline slope are proved.The angle between the main fracture surface and the plane of the sandstone slope is 20~26,and the boundary between the deteriorated rock mass at the toe of slope and the deformed rock mass at the upper part is taken as the boundary,and the fracture surface is in a near-straight shape upward from the cut-off point.The main failure mode in the anticline slope of sandstone is spalling,toppling and fracture.

关 键 词：GDEM 三峡库区 砂岩反倾岩质边坡 坡脚劣化 破坏机制 

分 类 号：TU457[建筑科学—岩土工程]