基于有限元小净距双隧洞开挖模拟

Excavation Simulation of Double Tunnels with Small Clear Distance Based on Finite Element Method

摘要: 最小净差隧道又称近接隧道、最近间距隧道等，是指当双线或分离型隧洞中的最大净距差小于或等于一点五倍洞径，或双隧洞中围岩厚度等于独立双隧洞最小净差的特殊隧洞布置。隧洞施工不可避免地会危害邻近建筑，小净距隧洞也应该充分考虑两个隧洞间的稳定性，以保证隧洞施工的安全性。利用有限元COMSOL软件仿真隧洞施工变形，构建隧洞施工变形二维有限元模型加以研究分析。地表沉降和隧道周围的塑性区域是预测开挖过程所必需的重要参数。经过分析，得出了土体开挖前的应力云图分析、地表沉降曲线和塑性区图。为遏制地面沉降、防护地基建筑物、制定隧洞衬砌及保护方法提供了重要依据，对隧洞施工有着重要性。

Abstract: The minimum net difference tunnel is also called proximity tunnel, nearest distance tunnel, etc. It refers to the special tunnel layout when the maximum net distance difference in the double track or separated tunnel is less than or equal to one point five times the tunnel diameter, or the thick-ness of surrounding rock in the double tunnel is equal to the minimum net difference of independ-ent double tunnels. The tunnel construction will inevitably endanger the adjacent buildings, and the stability between the two tunnels should also be fully considered for the small clearance tunnel to ensure the safety of tunnel construction. By using the finite element COMSOL software to simu-late the tunnel construction deformation, a two-dimensional finite element model of tunnel con-struction deformation is constructed for research and analysis. The surface settlement and the plastic zone around the tunnel are important parameters for predicting the excavation process. Through analysis, the stress nephogram analysis, surface settlement curve and plastic zone dia-gram before soil excavation are obtained. It provides an important basis for controlling ground set-tlement, protecting foundation buildings, and formulating tunnel lining and protection methods, which is important for tunnel construction.