既有建筑对地铁车站中洞法施工中支护结构内力影响的有限元分析

FEM Analysis of Forces for Support of an Existing Building During the Center Drift Construction of a Subway Station

中洞法是地铁车站施工中常用的施工方法,可以有效地提高开挖期间围岩的稳定性。拟建车站旁侧既有建筑可引起车站开挖导致的原场地应力不均衡,对支护结构内力形成不良影响。文章通过对某旁侧有建筑物的拟建车站中洞法施工进行了有限元数值模拟,计算分析了既有建筑对车站支护结构受力的影响,以及车站支护结构的内力特点与变化规律。结果表明,既有建筑会引起车站开挖过程中支护结构的受力偏转,进而引起局部不均匀沉降。

The center drift method is commonly used in the construction of subway stations because it effectively improves the stability of surrounding rock during excavation. The existence of buildings near a proposed station could cause an imbalance of in-situ stress around the excavation area, which could have an adverse effect on the supporting structure. Using FEM analysis on center drift construction, the bending moment of the support structure in every step of excavation was calculated, the effects of the existing building on the support structure were determined, and the characteristics and variation pattern of the internal force of the support structure are summarized. The results show that the existing building will cause force deflection of the supporting structure during the station excavation and further result in partial differential settlement.