| ABSTRACT:With the development of urbanization, the underground space continues to expand, and the Cave-pile construction technology is becoming a popular way of the urban subway construction. The method has achieved significant economic and social benefits in Beijing subway construction, showing broad prospects for development and good promotion value. Therefore, it is necessary to research the surface subsidence caused by the Cave-pile construction systematically, reducing the impact to environment caused by the construction. To further analyze the influence to surface subsidence resulted from the different stages of the Cave-pile construction, this paper conducts a detailed study in the following ways based on Puhuangyu Beijing Subway Line14station engineering.(1) Midas-GTS finite element software were used to simulate four kinds of pilot tunnel excavation program, then we analyzed the largest surface subsidence, vault settlement values, the horizontal displacement of the hole, cave uplift values, step by step settlement values, the average settlement rate and other indicators of the various program. By comparing, the optimal excavation program of pilot tunnel is the program â…£.(2) We used element software to simulate the dynamic construction process of Puhuangyu station which is similar to the site operation, then analyzed the ground settlement and settlement reasons caused by the four typical stages, which are the pilot tunnel excavation stage, the stage of arch construction, the stage of station hall construction and the stage of platform layer construction.(3) Through field data statistics, we analyzed the law of the surface subsidence caused by the actual various construction stages. In order to reduce surface subsidence of the Cave-pile construction, we compared the field data and numerical simulation results to summarize the law, thus making more constructive recommendations which is instructive for the similar projects in the future. |
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