水电工程左坝肩边坡稳定性强度折减有限元分析  

Strength reduction finite element analysis on slope stability of a hydropower project left abutment

作　　者：高丙丽[1] 

机构地区：[1]西安科技大学建筑与土木工程学院,陕西西安710054

出　　处：《西安科技大学学报》2014年第5期509-516,共8页Journal of Xi’an University of Science and Technology

基　　金：陕西省教育厅科研计划资助项目资助(2010JK667)

摘　　要：边坡失稳已成为全球性三大地质灾害之一,水电站坝区边坡的稳定性,是直接影响水电站工程的关键部分。针对水电工程坝址区地质条件复杂、开挖步序多的实际情况,结合岩体结构调查与结构面统计结果,将坝址区范围内岩体划分为2个分带,分析可知,在左坝肩处,开挖边坡受结构面组合影响,存在不利组合体,并给出了左坝肩边坡的主要破坏模式。采用三维有限元分析方法,建立计算模型,分析了某水电工程左坝肩边坡的稳定性,得到了边坡开挖卸荷、支护中的变形规律和和应力分布特性,给出边坡的破坏特征和部位。研究结果表明：左坝肩边坡的中下部790 m高程以下的稳定性较好,而稳定性较为薄弱的部位主要位于边坡中上部805~842 m高程。分级开挖过程对应部位坡面附近有拉破坏、剪破坏和拉剪破坏等多种破坏模式出现,但破坏分布深度一般在2.0 m范围以内。为了对设计开挖坡比、锚杆及喷锚支护,左坝肩边坡分级开挖完成后的整体稳定性有较为明确的量化依据,并宏观把握其潜在失稳趋势,采用强度折减系数法,得出边坡的整体稳定系数为1.48,并给出相应的边坡破坏模式,并在此基础上提出了边坡治理方案。工程实践表明,边坡工程稳定性分析结果和加固设计方案合理有效。Slope instability has become one of the three major global geological disasters. The stability of dam slope of hydropower station is a key part of the direct impact of hydropower station engineering. Aiming at the actual situation of the complex geological conditions and more excavation steps for a hydropower engineering dam area,combining the results of investigation of rock mass structure and structure statistics of structural planes,the rock mass in range of the dam site area is divided into two zones,analysis shows that,there are unfavorable combination blocks affected by combination of structural plane in the left abutment,and the main failure modes of the left abutment slope are given. By means of three-dimensional finite element method,the calculation model is established,and the stability of side slope of the left dam abutment of a hydropower project is analyzed. Obtaining deformation law and stress distribution characteristic of slope excavation during unloading and supporting. Failure characteristics and position of slope are given. The results show that,the slope stability is well below the altitude of 790 m in the lower part of the left abutment slope,while the slope of relatively weak stability is mainly located in the altitude from 805 m to 842 m in the upper part of the slope. There are much failure modes such as tension failure,shear failure and tension and shear failure near the slope of the corresponding part during slope stepped excavation,but the damage distribution depth is generally in the range of 2. 0 m. In order to have the definite quantitative basis of the design of excavation slope ratio,bolt and shotcrete and rock bolt support and the overall stability of the left abutment slope after the completion of stepped excavation,and grasp the potential instability trend macroscopically,the strength reduction coefficient method is used. The integral stability coefficient of slope and the failure mode of slope are given. Based on these results,treatment schemes of the slope are proposed. Practi

关 键 词：边坡 稳定性 三维有限元 强度折减法 加固 

分 类 号：P642[天文地球—工程地质学]