轨道交通车站主体工程的基坑监测

Foundation Pit Monitoring of Main Works in Rail Transit Station

以郑州市轨道交通5号线地下车站基坑的墙体最大水平位移和地表沉降监测为例,分析了基坑墙体水平位移、墙后地表沉降的变化规律。结果表明:受到软土土质的影响,基坑墙体水平位移和墙后地表沉降比较大。据此,控制基坑变形,及时进行施工底板垫层并增加底板垫层厚度,以增加被动抗力。由盆式分层开挖及时调整为水平开挖方式,支撑处采用开槽开挖并同时架设支撑,同时增加观测次数,加强对变形的监测,依据监测结果实施信息法施工,基坑得以顺利开挖完成。

The maximum horizontal displacement and surface settlement of the foundation pit of Zhengzhou Metro Line 5 underground station are monitored,and the variation rules of the horizontal displacement of the foundation pit wall and the surface settlement behind the wall are analyzed.The results show that the horizontal displacement of the foundation pit wall and the ground settlement behind the wall are relatively large due to the influence of soft soil.It is suggested to controlthe foundation pit deformation,then to construct the floor cushion in time and to thickenthe floor cushion so as to increase the passive resistance.The method of horizontal excavation is adjusted from the basin layered excavation,and the support is excavated by slotting and erecting at the same time,meanwhile,more observation is conducted to strengthen the monitoring of deformation.Based on the monitoring results,the construction of foundation pit reinforcement proves to be safe.