不入岩深基坑围护结构施工工艺研究

Selection of Construction Technology for Enclosure Structure of Deep Foundation Pit without Rock Penetration

常用于不入岩深基坑围护结构的施工工艺有排桩、咬合桩以及地下连续墙。基于昆明市轨道交通5号线弥勒寺站基坑围护项目,综合考虑不同施工工艺的地层适应性、施工效率、工程造价以及质量控制等因素,对该项目进行施工工艺比选。结果表明:仅采用排桩或咬合桩工艺一般施工无法满足部分施工场地穿过硬质圆砾层要求;排桩难以满足抗渗要求;仅采用地下连续墙作为围护结构则会造成工程造价过高,经济性较差。最终确定了以地下连续墙为主,咬合桩为辅的基坑围护结构施工工艺。

The commonly used construction technologies for the enclosure structure of deep foundation pit without rock penetration are the row pile,secant pile wall and underground diaphragm wall.Based on the foundation pit enclosure project of Milesi Station of Kunming Rail Transit Line 5,the construction technologies of the project are selected and compared by comprehensively considering the different construction technologies of stratum adaptability,construction efficiency,engineering cost,quality control and the other factors.The results show that only the row pile or secant pile wall technology cannot meet the requirement of some construction plants passing through the hard round gravel layer under the general construction.The row piles are difficult to meet the impermeability requirements.As the enclosure structure,only the underground diaphragm wall will bring about too high engineering cost and poor economy.Finally,the construction technology of the foundation pit enclosure structure with underground diaphragm wall as the main and secant pile wall as the auxiliary is determined.