考虑施工荷载作用的软弱地层深基坑稳定性研究

Study on Stability of Deep Foundation Pit in Soft Ground Considering Construction Load

临时盖板结构系统稳定性对地铁深基坑的安全起重要作用。依托福州长乐机场城际铁路祥谦站—首占站明挖区间深基坑工程,分别考虑限值施工荷载作用于两种厚度临时盖板,对临时盖板结构系统及基坑稳定性开展数值分析。结果表明,具有更大厚度的临时盖板在限值施工荷载作用下具有更强的抗变形能力,500与800 mm厚临时盖板在限值施工荷载作用下最大竖向变形分别为15.81与11.32 mm;在限值荷载作用下临时盖板对基坑结构造成的变形均小于3 mm,表明其可安全地作为普通车辆与渣土车辆通道或吊车及TBM运输通道。

The stability of temporary cover plate system plays an important role in the safety of deep foundation pit of subway.Relying on the deep foundation pit engineering of intercity railway of Xiangqian Station-Shouzhan Station of Fuzhou Changle International Airport,considering the limited construction load acting on two different thickness of temporary cover plate,numerical analysis was conducted on the temporary cover structure system and the stability of the foundation pit.The results show that the temporary cover plate with larger thickness has stronger anti deformation ability under the limited construction load.The maximum vertical deformation of 500 mm and 800 mm thick temporary cover plate under the limit construction load is 15.81 mm and 11.32 mm respectively;under the limit load,the deformation of the temporary cover plate to the foundation pit structure is less than 3 mm,indicating that it can be safely used as the passageway between ordinary vehicles and small construction vehicles,or as the transportation passageway of crane and TBM.