暗挖地铁车站空间交叉部位施工对地层管线变形影响及控制措施研究

Research on the Influence of Construction of Underground Subway Station's Spatial Cross Structure on Stratum&Pipeline and Corresponding Protective Measures

暗挖地铁车站施工横通道与车站主体结构空间交叉部位具有施工工序多、受力体系转换复杂、地层沉降叠加效应显著、对地下管线影响大等特点。以北京地铁16号线红莲南里站L1施工横通道与车站主体结构交叉部位为研究背景,建立交叉部位三维有限元计算模型,分析L1横通道交叉部位施工阶段的地层位移、管线变形和支护结构应力变化规律,计算结果表明:横通道与车站主体结构空间交叉部位施工在车站纵向地表沉降影响范围为25 m左右,横通道两侧的10 m范围为沉降叠加效应显著区域;横通道侧壁支护结构拉应力超过设计允许值;洞口部位的车站主体结构拱部出现拉应力。根据数值模拟结果,对交叉部位的横通道施工方案、车站主体结构开挖方案及支护措施进行了调整。沉降监测结果表明,地表沉降和管线变形得到了有效控制。

The construction of spatial cross structure between the construction channel and the main structure of underground subway station is characterized by multiple construction procedures,complex transformation of stress system,a significant superposition effect for ground subsidence and great influence on underground pipeline.Based on the research background of the intersection area between the L1 construction channel and the main structure of the station at Honglian Nanli Station of Beijing Metro Line 16,this paper establishes a three-dimensional finite element calculation model of the spatial cross structure,and analyzes the surface settlement,pipeline deformation and support structure stress variation caused by the construction of spatial cross structure.The calculation results show that the influence of the spatial cross structure construction on the longitudinal surface settlement of the station is ranged about 25 m,and the 10m range on both sides of the cross-channel is the area with remarkable settlement superposition effect.The tensile stress of the lateral wall supporting structure of the transverse passage exceeds the allowable value of design.The tensile stress appears in the arch of the station main structure located at the spatial intersection.According to the results of numerical simulation,the construction scheme of the cross passage,the excavation scheme of the main structure of the station and the supporting measures are adjusted.The results of settlement monitoring show that the surface settlement and underground pipeline deformation are effectively controlled.