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一个大的地下洞室(地下厂房、隧洞等)在开挖过程中需要扩大多次才能达到设计断面。每扩大一次周围岩面的应力和变形都会发生新的变化。每开挖掉一块岩体就如同在开挖面上失去了一部份支撑,而产生应力和变形增量,这种变化可以用原开挖面上施加相应的卸荷荷载来模拟。在编制地下结构计算的有限元程序中应当尽可能考虑实际开挖过程的连续模拟计算。为此要解决两个问题:1.如何在计算的实现洞室的分期开挖、洞室逐步扩大的完整过程的模拟,即如何灵活地减少单元和节点数。2.在逐步变化的开
A large underground cavern (underground buildings, tunnels, etc.) needs to be expanded several times during the excavation to reach the design section. Every time the stress and deformation of the surrounding rock surface are enlarged, new changes will occur. Every excavation of a rock mass is like losing a part of the support on the excavation surface, resulting in an increase in stress and deformation. This change can be simulated by applying the corresponding unloading load on the original excavation surface. In the preparation of the finite element program for the calculation of underground structures, the continuous simulation calculation of the actual excavation process should be considered as much as possible. To solve this problem, we must solve two problems: 1. How to realize the simulation of the complete process of excavation of tunnels and gradual enlargement of caverns in computation, that is, how to reduce the number of units and nodes flexibly. 2. In the gradual change of open