盾构隧道施工对邻近混凝土框架结构的影响分析

基于盾构施工对地层影响规律和现场实测资料,对因隧道下穿混凝土框架结构的变形、受力及其抵抗差异变形的能力进行了分析。研究表明:框架结构基础沉降较大的柱体承受上部荷载会减小,甚至出现拉力状况,相邻柱的轴压力和弯矩增大,横梁弯矩增大;对于老旧建筑物,配筋较少,对差异变形敏感,抵抗差异变形能力差;通过数值模拟计算得出不同工况下差异沉降,当单柱总沉降小于2 mm,差异沉降率小于0.35 mm/m时,盾构施工对建筑物影响较小,安全风险可控,并以此为安全风险控制指标指导施工;工程现场实测单柱最大沉降1.14 mm,柱间差异沉降斜率为0.06~0.29 mm/m,二者均在风险控制指标范围内,地铁下穿过程中框架结构稳定性保持良好。

Impact Analysis of the Shield Tunneling on the Adjacent Concrete-frame Structure

The deformation,stress and resistance ability of the different deformation of the concrete frame structure caused by shield tunneling based on the influence law of shield construction on stratum and field measurements were analyzed,the Research shows:the bearing upper load of the frame structure column will reduced,when the foundation settlement be larger,and even the tension will occur,the axial pressure and bending moment of the adjacent columns will increase,and the bending moment of the crossbeam will increase;For old buildings,the reinforcement is less,sensitive to differential deformation and poor resistance to differential deformation;Differential settlement under different working conditions is obtained by numerical simulation,it can be concluded that when the total settlement of a single column is less than 2 mm,and the differential settlement rate is less than 0.35 mm/m,shield construction has less impact on buildings,and the safety risk is controllable,and the construction is guided by this safety risk control index;The maximum settlement of a single column measured on site is 1.14 mm,and the differential settlement slope between columns is 0.06 mm/m?0.29 mm/m,both of which are controlled within the range of safety risk indicators.The frame structure is maintained in good condition during subway undercutting.