极端降雨下轨道交通车站深基坑安全分析与控制

Safety Analysis&Control of Deep Foundation Pit of Rail Transit Station under Extreme Rainfall

郑州7·20特大暴雨灾害,诱发众多基坑工程事故。针对极端降雨作用下轨道交通车站深基坑安全问题,依托实际工程,通过整理分析极端降雨条件下围护结构水平位移、钢支撑轴力以及地下管线竖向位移实测数据,探讨轨道交通车站基坑支护的安全性,并给出应急处理措施。研究结果表明,受暴雨灾害影响,桩体水平位移急剧增大,钢支撑轴力变化曲线随时间增长呈现出“几”字型变化曲线,轴力急剧上升,最大值超过设计值,基坑周边管线出现较大的竖向位移,基坑安全存在风险。极端降雨条件下应急处理时,应增加监测频率,封堵基坑涌水、渗漏点,排查基坑周边的空洞,并及时安排封堵回填等。

The July 20th Heavy Rain Disaster in Zhengzhou has caused many foundation pit engineering accidents.Aiming at the safety problem of deep foundation pit of rail transit station under extreme rainfall,relying on the actual project,through arranging&analyzing the measured data of horizontal displacement of retaining structure,axial force of steel support&vertical displacement of underground pipeline under extreme rainfall,the safety of foundation pit support of rail transit station is discussed,and the emergency treatment measures are given.The research results show that the horizontal displacement of the pile body increases sharply under the influence of the rainstorm disaster,and the change curve of the axial force of the steel support shows a几-shaped change curve with the increase of time.The axial force rises sharply,and the maximum value exceeds the design value.There is a large vertical displacement of the pipeline,and the safety of the foundation pit is at risk.During emergency treatment under extreme rainfall conditions,the monitoring frequency should be increased,the water inflow&leakage points of the foundation pit should be blocked,the voids around the foundation pit should be checked,and plugging&backfilling should be arranged in a timely manner.