下穿河道与桥梁基础的地铁车站围护结构加固及变形监测

Reinforcement and deformation monitoring of enclosure structure of subway station undercrossing rivers and bridge foundations

针对杭州地铁2号线良渚站主体结构下穿庙前港河道、杜甫桥桩基础侵入地下连续墙以及槽壁加固三个关键问题,采用钢板桩围堰加改迁河道进行庙前港导流、全回转拔桩清障施工工艺进行杜甫桥桩基础的拔除以及三轴搅拌桩槽壁加固三种施工方案。同时分别对基坑开挖过程中的墙顶沉降、地表沉降、墙体测斜以及土体测斜等变形监测值进行时间和空间上的分析。监测数据表明:采用三轴搅拌桩槽壁加固技术能够保证地连墙开挖过程中槽壁的稳定性,从而在一定程度上减小地连墙墙体变形及整体水平移动,同时有效减少地连墙附近的地表沉降值。

In view of the three key problems including the main structure of Hangzhou Metro Line 2 Liangzhu station undercrossing the Miaoqiangang river,the pile foundation of Dufu bridge intruding the underground continuous wall and groove wall reinforcement,three construction schemes were proposed,which include the diversion of Miaoqiangang river by using steel sheet piling cofferdam,the removal of Dufu bridge pile foundation by using the construction technology of full-rotating pile pulling and groove wall reinforcement construction by using tri-axial mixing pile.At the same time,the time and space analysis of the deformation monitoring,such as the settlement of the top of the wall,the settlement of the ground surface,the inclination of the wall and the inclination of the soil were carried out.The monitoring data show that,adopting the groove wall reinforcement technology of tri-axial mixing pile can ensure the groove wall stability during the excavation of underground continuous walls,thus decreasing the deformation and integral horizontal movement of underground continuous walls in a certain degree and effectively reducing the settlement value of ground surface.