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随着地下洞室工程建设的增多,在复杂地质条件及动力条件下的地下洞室的稳定性受到越来越多的重视,其抗震稳定性及加固设计成为保证工程安全运行的重要课题。基于变形加固理论和过应力概念,提出采用塑性余能范数及不平衡力时程评价结构整体稳定性及局部失稳的分析理论。基于三维非线性有限元动力分析,提出适用于地下工程结构抗震稳定性评价的分析方法,并在三维非线性有限元程序TFINE中实现。地下工程结构稳定性的最危险状态通过塑性余能范数时程曲线来确定。通过不平衡力大小及分布的时程变化来确定容易破坏的部位,同时也可以为支护设计提供指导。对隧洞模型的应力位移反应做了分析,并将屈服区与不平衡力分布进行对比,并分析有、无衬砌对结构稳定性的影响。计算结果表明,不平衡力可以直观地表示结构的局部失稳情况,比采用位移、应力和围岩屈服区评价隧洞围岩稳定性更为准确、有效,塑性余能范数可以定量评价隧洞围岩的整体稳定性及围岩衬砌效果。
With the increase of construction of underground caverns, the stability of underground caverns under complex geological conditions and dynamic conditions has received more and more attention. Its seismic stability and reinforcement design have become important topics to ensure the safe operation of the project. Based on the theory of deformation reinforcement and the concept of over stress, an analytical theory is proposed to evaluate the overall stability and local instability of the structure using plastic residual energy norm and unbalance force. Based on the three-dimensional nonlinear finite element dynamic analysis, an analytical method suitable for the seismic stability evaluation of underground structures is proposed and implemented in the three-dimensional nonlinear finite element program TFINE. The most dangerous state of underground structural stability is determined by the plastic residual energy norm time history curve. Through the unbalanced force size and distribution of the time course changes to determine the vulnerable parts, but also can provide support for the design guidance. The stress-displacement response of the tunnel model is analyzed, and the yield zone is compared with the unbalanced force distribution. The influence of the non-lining on the structural stability is also analyzed. The calculated results show that the unbalanced force can intuitively represent the local instability of the structure. It is more accurate and effective than using the displacement, stress and surrounding rock yielding area to evaluate the surrounding rock stability of the tunnel. The plastic residual energy norm can quantitatively evaluate the tunnel surrounding The overall stability of rock and surrounding rock lining effect.