深厚软土区基坑施工对临近地铁隧道影响分析

Analysis on Influence of Foundation Pit Construction on Adjacent Subway Tunnels in Deep Soft Soil Area

摘要:

针对深厚淤泥质软土地区、高承压水等不利条件下的基坑开挖对临近运营地铁隧道结构影响问题，以临近武汉地铁2号线某综合管廊基坑施工为背景，构建了三维数值分析模型，系统分析了基坑施工对自身围护结构变形、地铁隧道结构位移及受力的影响。研究结果表明：基坑开挖引起的围护结构水平向、竖向最大位移值分别为11.5 mm、1.44 mm，地铁隧道结构最大水平向、竖向位移分别为0.42 mm、0.21 mm，盾构管片最大轴力、剪力及弯矩分别为1 479.65 kN/m、48.38 kN/m、109.77 kN·m/m，数值分析结果均在规范限值以内。研究成果可为类似基坑施工对临近建构筑物安全风险评估提供借鉴。

Abstract:

In view of the influence of foundation pit excavation on the structure of adjacent operational subway tunnels under the unfavorable conditions of deep muddy soft soil area and high confined water, taking the foundation pit construction of a utility tunnel near Wuhan Metro Line 2 as the background, a three-dimensional numerical analysis model is built systematically to analyze the influence of the foundation pit construction on the deformation of its enclosing structure, and the displacement and stress of the subway tunnel structure. The results show that the maximum horizontal and vertical displacements of the enclosing structures caused by the foundation pit excavation are 11.5 mm and 1.44 mm respectively, the maximum horizontal and vertical displacements of the subway tunnel structure are 0.42 mm and 0.21 mm respectively, and the maximum axial force, shear force and bending moment of the shield segment are 1 479.65 kN/m, 48.38 kN/m and 109.77 kN/m respectively. The numerical analysis results are all within the standard limiting values. The research results can be referred for the safety risk assessment of the adjacent buildings and structures in the similar constructions of foundation pits.