不同侧应力状态下混凝土循环加卸载损伤特性研究  

Cyclic Loading and Unloading Dynamic Damage Properties of Concrete under Different Lateral Stress

作　　者：刘博文[1] 罗曦[1] 马小亮[1] 王孝政[1] 

机构地区：[1]三峡大学土木与建筑学院,443002

出　　处：《灾害与防治工程》2015年第2期25-31,44,共8页Disaster and Control Engineering

基　　金：国家自然科学基金（51279092）

摘　　要：采用大型多功能液压伺服静动力三轴仪对不同侧压比的混凝土进行应变速率为10^-4／s的等应变循环加卸载试验，对试验所得的应力一应变曲线中的滞回环进行分析，探究侧压比对循环加卸载曲线中的滞回环与混凝土损伤的关系，最后建立损伤估计模型并进行分析。得出主要结论如下：混凝土加卸载过程由于自身塑性存在应变恢复滞后现象，滞回环在每次卸载初始阶段应力下降而变形恢复很慢，随着应力的逐渐下降应变恢复才开始加快；混凝土的单位耗散能随着循环次数的增加均先增大后减小，在循环次数相同时，耗散能随着侧应力的增加而增加，且增加幅度明显，表明单位体积耗散能具有明显的侧应力敏感性；基于滞回环面积与混凝土的耗散能关系，建立不同侧压比下混凝土循环加卸载损伤估计模型；分析得出不同侧压比下混凝土损伤演化路径不同，但演化路径的起点终点重合。随着侧压比增加，混凝土损伤演化路径后移，同等循环次数下，侧压比越小混凝土的损伤越大。The large-scale multi-function hydraulic servo Static and dynamic triaxial com- pression ratio on different sides of the concrete and other strain cyclic loading tests, stress tests were perfo- rmed- strain curve hysteresis loop to analyze, explore side pressure ratio of cyclic unloading curve of hysteresis loop and concrete injury, damage estimation model finally set up and analyzed. The main conclusions are as follows： The process of loading and unloading concrete presence of plastic strain recovery due to its hysteresis hysteresis loop in the initial stage of each unloading decrease stress and deformation recovery is very slow, gradual decline with the stress-strain reco-very began to accelerate; Units concrete dissipated energy increases with the number of cycles after the are first increased and then decreased; the same, the dissipated energy increases lateral stress increases in the number of cycles, and the rate of increase significantly, obviously dissipated energy per unit vol- ume . The lateral stress sensiti-vity~ Based on the relationship between hysteresis loop area of energy dissipation and concrete, to establish dif-ferent lateral pressure of concrete under cyclic loading and unloading than damage estimation model~ Different lateral pressure of concrete under different evolutionary path than the damage. While, the starting point coin- cides with the end of the evolutionary path. With the increase of lateral pressure ratio, concrete damage evolution path a-fter shift. Under the same cycles, lateral pressure greater damage than smaller concrete.

关 键 词：滞回环 侧压比 耗散能 损伤估计模型 损伤演化 

分 类 号：TU528.01[建筑科学—建筑技术科学]