双线平行盾构掘进对邻近浅基础建筑物影响理论分析

Theoretical Study of Influence of Double-Line Parallel Shield Tunneling on Adjacent Frame Building with Shallow Foundation

为解决双线平行盾构隧道施工对邻近浅基础建筑物的变形及弯矩变化的影响问题,并对实际掘进工况给出施工建议,利用Sagaseta纵向地表变形计算公式,推导出双线平行盾构掘进影响区内浅基础建筑物地基、基础和结构协同作用的力学模型,分析得到浅基础框架建筑物变形以及弯矩变化规律。研究结果表明:盾构隧道掘进区内,浅基础框架建筑物的弯矩大小随着开挖面的靠近逐渐增大,开挖面到达建筑物正下方附近时达到最大值,之后又逐渐减小;建筑物倾斜率越大,梁端弯矩和底层柱对基础的约束弯矩也越大;双线平行盾构先后掘进相比同时掘进引起的建筑物倾斜更小、沉降变化更加缓和,框架结构及基础梁的弯矩更小,且随着先后掘进开挖面距离的增大,弯矩变化曲线逐渐由V型转变成W型;建议双线平行盾构施工时尽量避免同时掘进,并进一步加强对建筑物首尾沉降差及倾斜率的监测。

A mechanical model for interaction among double-line parallel shield tunneling and ground, foundation andstructure of foundation of adjacent building is deduced and established by Sagaseta formula of longitudinal ground surfacedeformation, so as to study the influence of double-line parallel shield tunneling on deformation and bending moment ofadjacent frame building with shallow foundation. The results show that ： 1 ） The bending moment of the frame buildingincreases with the horizontal distance between building and shield boring face decrease; and it reaches peak when shieldboring face reaches bottom center of building. 2） The restraining moment of beam end and bottom column to foundationincrease with tilt of the building increase. 3 ） The influence of shield tunneling one line after another on the building issmaller than that of double-line shield tunneling synchronously. The bending moment curve of building slowly turns intoW shape from V shape with the distance between boring face of two line increase. 4） The authors suggest that the twotunnels should not be bored synchronously; and monitoring of the building should be strengthened.