水工隧洞钢筋混凝土衬砌非线性有限元分析

Nonlinear finite element analysis of reinforced concrete lining of hydraulic tunnels

在已有岩土程序的基础上,考虑混凝土材料的开裂特性,增加了钢筋和混凝土开裂的模拟功能,编制了相应的非线性有限元计算程序,实现了塑性迭代和开裂迭代计算的耦合。结合某水电站导流隧洞的工程实例,进行了施工、运行和封堵全过程仿真分析。计算过程显示:本算法迭代计算稳定,收敛性好,满足精度要求。同时研究结果表明:运行期,混凝土衬砌的开裂范围、裂缝宽度和相应的钢筋应力随着衬砌与围岩之间初始缝隙值的增大而增大;封堵期,围岩塑性区随着外水位的增加而增大,需要采取相应的加固措施保证围岩稳定。

Based on a program for geotechnical engineering, the functions of modeling reinforcing bar and cracking of concrete are supplemented; and a corresponding nonlinear FEM program is developed. The combination of cracking and plasticity in iterative calculation has also been achieved. Then, in accordance with the practice of a diversion tunnel for a certain hydropower station, the whole procedure consisting of construction, operation and plugging has been analyzed. The process shows that the algorithm routine has good stabilization and convergence, and can meet the requirement of accuracy. The results show that the crack extent, the crack width and the reinforced bar stresses increase with the increment of the original gap width in the operation; and the plastic zone in rock increases with the rising of the outside water level. So some measures should be taken to keep the rock stable in plugging time.