跨特大型溶洞隧道桩基承台跨越结构力学响应分析

Mechanical Response Analysis of Pile Foundation Bearing Platform Spanning Structure of Tunnel Across Super Large Karst Cave

在隧道建设穿越溶洞尤其是特大型溶洞过程中,选择合理的跨越结构至关重要。本文以某隧道跨特大型竖井溶洞段为依托,基于有限差分软件FLAC^(3D),研究隧道桩基承台跨越结构力学响应,并对其稳定性进行分析。结果表明:跨越结构应力主要集中于和围岩接触部位的桩基下部及承台边缘,应进一步提升桩基承台结构与围岩的连接强度;桩基承台结构右侧承台边缘区域位移超出安全控制指标预警值,应加强该区域监测以保障施工安全,必要时采取强化措施。

In the process of tunnel construction through caves,especially super large karst caves,it is very important to choose a reasonable spanning structure.In this paper,based on FLAC^(3D) finite difference software,the mechanical response of the pile foundation bearing platform spanning structure of a tunnel is studied and its stability is analysed based on the section of a tunnel spanning a super large karst cave.The results show that:the stress of the spanning structure is mainly concentrated in the lower part of the pile foundation and the edge of the bearing platform in the contact area with the surrounding rock,and the strength of the connection between the pile foundation bearing platform structure and the surrounding rock should be further improved;the displacement of the right side of the pile foundation bearing platform structure in the edge area of the bearing platform exceeds the warning value of the safety control indexes,so the monitoring of this area should be strengthened to ensure the safety of the construction and the reinforcing measures should be taken when necessary.