重力坝加高的应力和稳定计算方法及控制标准研究  

Study on calculation method and control standard of stress and stability of the gravity dam heightening

作　　者：张国新[1] 钮新强 雒翔宇 颜天佑 ZHANG Guoxin;NIU Xinqiang;LUO Xiangyu;YAN Tianyou(State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin,China Instit-ute of Water Resources and Hydropower Research,Beijing 100038,China;Changjiang Survey,Planning,Design and Research Co.,Ltd,Wuhan 430010,China)

机构地区：[1]流域水循环模拟与调控国家重点实验室,中国水利水电科学研究院,北京100038 [2]长江勘测规划设计研究有限责任公司,湖北武汉430010

出　　处：《水利学报》2022年第4期392-402,共11页Journal of Hydraulic Engineering

基　　金：中国水利水电科学研究院人才托举项目(SS110145B0052021)。

摘　　要：后帮式重力坝加高存在新老混凝土结合面和新老坝块分载的问题,结合面有限结合部分传力时传统的材料力学法和整体刚体极限平衡法不再适用于应力和稳定计算。本文介绍了重力坝加高模拟的有限单元法,提出了新老坝块应力和稳定计算的有限元等效法,以丹江口7#坝段为例进行了不同结合面状态的多工况计算,与弹塑性有限元强度折减法进行了比较。结果表明:(1)有限元等效内力法可以考虑结合面脱开、新老坝块材料差异、基础非均质性等复杂条件,同时可消除坝踵、新老混凝土结合处的应力集中,具有有限单元法和材料力学法两者的优势,其等效内力计算可通过应力积分法和直接反力法实现,直接反力法得到的等效内力精度更高;(2)采用有限元等效法计算坝基应力和整体及新老坝块局部稳定安全系数时,应力和稳定的控制标准应满足现行规范要求;(3)新老混凝土界面有限结合部分传力时,应力不利工况是贴坡段下部张开,而稳定不利工况是结合面上部张开、下部粘结;(4)丹江口7#坝段斜坡段中下部粘结面积20%以上时应力和温度均满足规范要求,该结论与“后帮有限结合”理论一致;(5)弹塑性有限元法是分析重力坝加高的有效方法,当采用与材料力学及刚体极限平衡法相同的计算模型及屈服准则时,可以得到相同的结果,可采用相同的控制标准,但当采用不同模型及准则时控制标准需要另行研究。In the raising of gravity dam by thickening back slope,there are problems of load sharing and interface bonding between new and old dam blocks.When the force is transmitted by partial interface,the traditional material mechanics method and integral rigid body limit equilibrium method are no longer suit-able for stress and stability calculation.This paper introduces the finite element method for the simulation of gravity dam heightening,and puts forward the finite element equivalent method for stress and stability calculation of new and old dam blocks.Taking Danjiangkou dam 7#section as an example,the multi-con-dition calculation of different interface states is carried out,which is compared with the elastic-plastic fi-nite element strength reduction method.The results show that:1)the finite element equivalent internal force method can consider the complex conditions such as separation of interface,material difference be-tween new and old dam blocks,and foundation heterogeneity,and it can eliminate the stress concentration at dam heel and contact point of new and old concrete by the finite element equivalent internal force meth-od.It has the advantages of finite element method and material mechanics method.Its equivalent internal force can be calculated by stress integration and direct reaction force method,The accuracy of equivalent internal force obtained by direct reaction force method is higher;2)When the finite element equivalent method is used to calculate the dam foundation stress and the safety factor of overall and local stability of new and old dam blocks,the control standard for stress and stability shall meet the requirements of cur-rent specifications;3)When the force is transmitted from the partial interface between new and old con-crete,the unfavorable condition of stress is the opening of the lower part of the slope section,while for dam block stability the unfavorable condition is the opening of the upper part and the bonding of the lower part of the interface;4)When the bonding area of the middle

关 键 词：后帮式 重力坝加高 有限元等效法 新老混凝土结合 

分 类 号：TV314[水利工程—水工结构工程]