高坝坝基挤压蚀变破碎带处理措施三维数值分析  

Numerical modeling on treatment of mylonitization and fracture belt in dam foundation

作　　者：徐卫亚[1] 孟国涛[1] 江涛[1] 杨清[2] 

机构地区：[1]河海大学水利水电学院,江苏南京210098 [2]中国水电顾问集团昆明勘测设计研究院,云南昆明650051

出　　处：《水利学报》2007年第3期312-318,共7页Journal of Hydraulic Engineering

摘　　要：挤压蚀变破碎带是水电站坝基的主要工程地质问题。基于重力坝坝体与坝基岩体联合作用的数值模拟，分析了某水电站挤压蚀变破碎带C23对坝体应力和变形的影响。在对多种加固处理措施比较的基础上，提出了建议方案，说明了处理方案对拉应力的控制效果。进而，就建议方案所对应的数值模型，对C23带进行了浮值分析，用强度储备系数法计算了受C23带影响的坝基安全稳定性，检验了加固措施的合理性。研究结果，建议采取的坝体上游不贴角措施、C23带倾斜开挖置换5m、下游坝趾填角3—5m方案可以有效控制由于C23带不均匀沉降引起坝趾区的拉应力，使拉应力范围大大缩小的同时使得拉应力值降低至处理前的1／3以下。强度储备系数法得出正常荷载组合下各坝段安全储备系数均不低于2．5，重力坝的安全稳定性有充足的裕度。建议处理方案同时满足拉应力控制及稳定性要求。A nonlinear 3-D numerical modeling was carried out for investigating the stress-deformation status of the gravity dam and the influence of fracture belt on stability of dam foundation in a hydropower project. Based on the comparison of numerical computational results of different treatments a scheme for reinforcing the dam foundation was proposed . It is found that the uneven displacement of the mylonitization and fracture belt results in the occurrence greatly affects the stress status of the dam. The proposed of high tensile stress at the toe of the dam and treatment including keeping the configuration of the dam toe as a vertical surface, excavating an oblique pit of the fracture belt with 5m depth and filling with concrete with height 3m to 5m. By adopting this treatment the tensile stress region at dam toe was greatly reduced and the stress was decreased by 2/3. This effectiveness of this measure and the stability of the dam are verified by the computational result of strength reserve coefficient method

关 键 词：数值模拟 岩体 挤压蚀变破碎带 重力坝 强度储备系数法 高坝坝基 

分 类 号：TV551.4[水利工程—水利水电工程]