缝水压力作用下坝踵裂缝动态应力强度因子分析  

Analysis on dynamic stress intensity factors of gravity dam heel cracks under in-crack water pressure

作　　者：胡良明[1] 杨旭[1] 贾欣 李姝钰 HU Liangming;YANG Xu;JIA Xin;LI Shuyu(School of Water Resources and Environment,Zhengzhou University,Zhengzhou 450001,China)

机构地区：[1]郑州大学水利与环境学院,河南郑州450001

出　　处：《人民长江》2020年第7期188-192,199,共6页Yangtze River

基　　金：国家自然科学基金青年基金资助项目(51609217)。

摘　　要：关于动载作用下混凝土重力坝坝踵裂缝水力劈裂的研究较少。应用扩展有限元法对缝水压力及地震作用下的重力坝坝踵裂缝进行动态数值模拟,使用相互作用积分方法求解裂尖应力强度因子,根据最大周向拉应力准则判断裂缝扩展情况。研究了加载过程中坝基与坝体的弹模比、缝内水压分布形式及初始裂缝长度对裂尖应力强度因子的影响,并模拟坝踵初始裂缝扩展过程。研究结果表明:当弹模比相差较大时,初始裂缝长度对裂缝扩展影响较大;而当坝基条件较差时,缝水压力是主要因素;弹模比是影响裂缝断裂特性的主要因素。坝体坝基界面初始裂缝在加载中呈周期性沿15°角斜向下扩展。数值模拟结果符合工程实际,可供研究重力坝界面断裂问题参考。The researches on hydraulic fracturing of concrete gravity dam heel crack under dynamic load are inadequate. In this paper, the extended finite element method was adopted to carry out the dynamic numerical simulation on crack in gravity dam heel under in-crack water pressure and earthquake action. The interaction integral method solved the stress intensity factor at the crack tip, and the crack propagation was judged according to the maximum circumferential tensile stress criterion. We studied the influence of the elastic modulus ratio of dam foundation to dam body, the distribution form of water pressure in the crack and the initial crack length on the stress intensity factor at the crack tip during the loading process, and simulated the initial crack propagation process of the dam heel. The results showed that when the elastic modulus ratio was quite different, the initial crack length was the main factor affecting the crack propagation. When the dam foundation conditions were poor, the in-crack water pressure was the main factor. Elastic modulus ratio was the main factor affecting fracture characteristics. The initial cracks at the dam body and dam foundation interface periodically spread downward along an angle of 15 degrees during loading. The numerical simulation results are in accordance with the engineering practice and can be used as a reference for study on interface fracture of gravity dams.

关 键 词：应力强度因子 坝踵裂缝 重力坝 缝水压力 地震响应 扩展有限元法 

分 类 号：TV313[水利工程—水工结构工程]