原位扩建隧道围岩变形及力学特性研究

Research on Wallrock Deformation and Mechanical Properties of In-Situ Expansion Tunnel

隧道原位扩建需要将原有结构拆除后再进行隧道扩挖,形成大断面隧道。从原隧道的开挖形成小断面隧道到拆除原有结构再扩挖成大断面隧道,围岩经过多次扰动后,经受的应力状态错综复杂。以大帽山隧道原位扩建为例,介绍采用数值模拟手段建立新建4车道和原位扩建4车道隧道的力学计算模型,得出原位扩建隧道的围岩变形及力学特性,为该隧道的支护结构设计提供依据。

As one of tunnels on expressway from Quanzhou to Xiamen, Damaoshan Tunnel has two lanes in original design, which are expanded to 4 lanes in situ for need of expansion. In-situ expansion of tunnel needs enlarge excavation of tunnel after removing original structures to form a large-section tunnel. From excavation of original tunnel to form small-section tunnel to large-section tunnel by removing original structures surrounding rocks experience complicated stress states after multiple disturbances. Based on insitu expansion of Damaoshan Tunnel as an example, this paper adopts numerical simulation to establish mechanical computation models of newly constructed 4 lanes and expanded 4 lanes in-situ and obtains surrounding rock and mechanical properties of in-situ expansion tunnel.