循环荷载下考虑滞回效应的混凝土损伤模型  

Damage Model of Concrete Considering Hysteretic Effect Under Cyclic Loading

作　　者：刘智 赵兰浩[2] 吴晓彬[1] 胡国平[1] 周清勇 LIU Zhi;ZHAO Lanhao;WU Xiaobin;HU Guoping;ZHOU Qingyong(Jiangxi Provincial Inst.of Water Sci.,Nanchang 330029,China;College of Water Conservancy and Hydropower Eng.,Hohai Univ.,Nanjing 210098,China)

机构地区：[1]江西省水利科学研究院,江西南昌330029 [2]河海大学水利水电学院,江苏南京210098

出　　处：《工程科学与技术》2020年第4期117-123,共7页Advanced Engineering Sciences

基　　金：国家重点研发计划项目(2016YFC0401601,2018YFC0406705);江西省水利厅科技计划项目(202022YBKT04)。

摘　　要：随着中国二次能源结构逐渐优化,大批高混凝土坝工程在西南地区应运而生,其抗震安全问题日益突出。针对高混凝土坝地震过程中复杂材料非线性问题,建立循环荷载下考虑滞回效应的混凝土损伤模型。模型分别选取符合混凝土实际变形特性的拉伸与压缩骨架线以考虑材料拉压异性,骨架线中含有软化段系数以适应试验结果的离散性。采用不依赖于骨架线形状的滞回效应加卸载特征点表达式,搭建能够反映混凝土循环荷载作用下软化段滞回效应的卸载路径与重新加载路径,并建议设立残余应变临界值解决残余塑性应变与卸载应变比值随应变增长的持续发散问题。模型将复杂多轴问题转化至单轴等效应变空间中求解,计算参数少,数学表达式简单,并通过对比混凝土循环拉伸荷载试验和Koyna重力坝的震害模拟验证了模型在非线性问题求解上的正确性与高效性。研究为高混凝土坝的抗震分析及安全评价提供理论支撑。With the gradual optimization of China secondary energy structure,a large number of high concrete dam projects have emerged in the southwestern region,and their seismic safety issues have become increasingly prominent.A concrete damage model considering hysteresis effect under cyclic loading was developed to solve the complicated material non-linear problem during high concrete dam earthquake.The tension and compression skeleton curves that conform to the actual deformation characteristics of concrete were used in the proposed model for adapting to the anisotropy of material tension and compression.The skeleton curves contained the softening section coefficient to adapt to the dispersion of test results.The expression of characteristic points of loading and unloading hysteresis effect that did not depend on the shape of the skeleton curve was used to establish an unloading path and a reloading path that reflected the hysteresis effect of softening section under the cyclic loading of concrete.A critical value of residual strain was suggested to solve the continuous divergence problem,that the ratio of residual plastic strain to unloading strain increased with the unloading strain.The model transmitted the complex multi-axis problem to a uniaxial equivalent strain space for problem solving,with fewer calculation parameters and simple mathematical expressions.The reliability and efficiency of the proposed model were investigated for nonlinear problems solving by comparing the concrete cyclic tensile load test with the earthquake damage simulation of Koyna gravity dam.This study can provide effective theoretical support for seismic analysis and safety evaluation of high concrete dams.

关 键 词：损伤模型 循环荷载 滞回效应 抗震分析 

分 类 号：TV312[水利工程—水工结构工程] TV314