重叠隧道爆破振动对相邻结构的影响

以某地铁工程区间近距离重叠隧道为背景，研究地铁区间隧道施工期间，爆破荷载对相邻隧道结构的影响。首先根据爆破振动加速度波确定爆破振动荷载，然后采用释放荷载方法模拟地铁隧道的开挖效应，确定初始应力场并通过对土一地铁结构体系进行模态分析，得到体系的振型和频率，以确定合理的阻尼系数和时间积分步长。最后运用Newmark隐式时间积分法，研究地铁区间近距离重叠隧道的动力响应。确定了在爆破振动荷载作用下衬砌结构的薄弱部位及其相应的位移和应力，得到地表的振动参数及其衰减值。得出的结论对设计和施工具有一定的指导意义。

INFLUENCES OF EXPLOSIVE VIBRATION IN OVERLAPPING TUNNELS ON ADJACENT STRUCTURES

The overlapping tunnels in a subway project are considered as the study background, and the influence of explosive vibration in overlapping tunnels on adjacent structure is studied during the subway project construction. The explosive vibration loadings are obtained by analyzing acceleration of explosive vibration. The initial stresses after excavation are calculated with stress relaxation method. The rational time step and damping of vibration analysis are defined by vibration modes and frequencies that are obtained with modal analysis. On the basis of Newmark step-by-step time integration method, the dynamic response of overlapping tunnels caused by the explosive vibration is analyzed. The stresses, displacements, and weak portions in the liner are determined under vibration loadings and static loadings. The vibration parameters and attenuation values in ground are achieved, and the results can be referred to tunnel design.