复杂条件下盾构下穿过站对既有结构影响分析及方案决策

NUMERICAL A NALYSIS OF INFLUENCE OF SHIELD PASSING THROUGH STATION ON EXIST ING STRUCTURE AND SCHEME DECISION-MAKING UNDER C OMPLEX CONDITIONS

在工程环境复杂的城市核心区,地铁修建首先需要考虑实施条件、工期情况以及整体的筹划,在此基础上针对每个具体的部位选择合理的实施方案以及具体的控制措施。本研究通过阐述王府井站–前门站区间盾构始发的困境,结合现场实际情况,采用包容性设计。并通过对车站东侧暗挖段工法及盾构下穿时机比选,采用在4导洞PBA工法的基础上增加管幕棚护措施及超前注浆加固措施的控制方案,并在桩基施工后进行盾构过站。在这种技术控制方案下,对盾构下穿过站对暗挖段以及上部建筑变形影响进行数值模拟分析,论证技术方案合理可行性。本研究提炼出的“万能”盾构始发条件预留思路,以及对重难点问题的专题研究和探讨,对本工程实施的稳步推进起到了至关重要的作用,也为后续类似工程的建设提供了借鉴。

In the urban core area where the engineering environment is particularly complex,the subway construction must first consider the implementation conditions,the construction schedule and the overall planning,on this basis for each specific part to select a reasonable implementation program and specific control measures.In this paper,the starting difficulties of the shield machine in Wangqian section are described,and the inclusive design is adopted in the implementation of the station.Through the comparison and selection of the construction method of underground excavation and the time of shield tunneling in the east side of the station,the control scheme of adding the measures of pipe curtain and advanced grouting reinforcement on the basis of the PBA construction method of 4-lead tunnel is adopted,and shield passing through the station after pile foundation construction.Under this technical control scheme,the influence of shield passing through station on the deformation of subsurface excavation section and superstructure is analyzed by numerical simulation,and the reasonable feasibility of the technical scheme is demonstrated.In this paper,the train of thought about the initial conditions of universal shield machine,as well as the research and discussion on the key and difficult problems,play an important role in the steady progress of the project,it can also provide reference for the following similar projects.