复杂岩基上高拱坝坝基坝肩浅层卸荷影响与稳定性研究  

Study on Influence of Dam Foundation Shallow Unloading and Stability of High Arch Dam with Complicated Rock Foundation

作　　者：杨宝全[1] 张林[1] 胡成秋[1] 陈建叶[1] 

机构地区：[1]四川大学水力学与山区河流开发保护国家重点实验室,水利水电学院,四川成都610065

出　　处：《四川大学学报（工程科学版）》2011年第5期71-76,共6页Journal of Sichuan University (Engineering Science Edition)

基　　金：国家自然科学基金资助项目(50879050);国家重点基础研究发展计划资助项目(2010CB226802);博士学科点专项科研基金资助项目(20100181110077)

摘　　要：采用3维地质力学模型综合法试验以及非线性有限元计算,对考虑浅层卸荷影响的小湾拱坝与地基整体稳定问题进行研究。试验中,用不同尺寸、不同力学参数的微小菱形块体对开挖出现的浅层松弛卸荷岩体进行重点模拟,同时还模拟了坝基坝肩主要的地质构造和加固方案,对主要的断层采用变温相似材料模拟,以便进行降强试验;有限元计算采用与模型试验一致的力学参数以及降强、超载步骤,对坝基浅层卸荷带用加密单元进行模拟。通过模型试验及计算分析得出,受坝基浅层卸荷的影响,在超载过程中坝踵和坝趾附近岩体首先出现开裂(对应模型试验)或产生塑性区(对应计算),最终上游坝踵附近裂缝或塑性区贯通,说明坝基浅层卸荷对坝与地基稳定性有一定影响,为保证运行后工程安全,建议对中下部高程坝基采取固结灌浆等加固措施。Considering the influences of shallow unloading and relaxation rocks,a 3D geo-mechanical model test and 3D nonlinear FEM calculation were carried out to study the global stability of high arch dam and foundation of Xiaowan Project,using different sizes and mechanical parameters of rhombus small blocks.At the same time,the main geological structures and the reinforcing schemes at the dam abutment and dam foundation were simulated.In order to carry out strength-decreasing test,the major weak structural planes were simulated using temperature analogous material.The shallow unloading zone of dam foundation was simulated using dense element.The model tests and calculations showed that the rocks nearby the dam heel and dam toe cracked firstly（corresponding to model test） or appeared plastic zone firstly（corresponding to calculation）,affected by the shallow unloading rocks in the process of overloading test,and finally the crack or the plastic zone transfixed nearby the upstream dam heel,which showed the shallow unloading rocks have a certain influence on the stability of dam and foundation.

关 键 词：坝基浅层 开挖卸荷 地质力学模型试验 有限元计算 整体稳定性 

分 类 号：TV321[水利工程—水工结构工程]