深开挖有限元分析中释放荷载模拟--三种常用方法比较及改进的Mana法

论述深开挖有限元分析中释放荷载的三种模拟方法——Mana法、单元应力内插法和位移法.通过实例对比分析指出位移法精度最高，但程序处理较繁琐；单元应力内插法计算效果最差，编程也不方便；Mana法概念明确，易于程序处理，但第一级开挖荷载偏大，以致影响以后各级的计算效果.文中对Mana法改进后，计算精度明显提高.

Simulation of Unloading due to Excavation in F.E.Analysis-Modified Mana Method Based on Comparison of Three Methods

In this paper,three methods for simulating the unloading due to excavation such as the displacement method,the stress method and the Mana method are compared in detail.It is shown that the accuracy of the displacement method is the best,but its computational program is complex;the accuracy of the stress method is the worst and program is difficult;the concept of the Mana method is precise,and it is easy to program,but the load for the first stage excavation is on the large side and affects the accuracy of calculation for the excavation that follows.Finally an improved Mana method is presented.