Study On Subsidence Characteristics Of A PBA Method Subway Station In Beijing

In recent years,major cities throughout the country have vigorously developed underground railway rail transit.By December 2017,22 subway lines with 608 kilometers were in operation in Beijing.By the end of 2020,Beijing is expected to have a subway-network with 1177 kilometers and 30 subway lines.In areas with dense buildings,heavy traffic or complicated pipelines,are constructed,The control requirements for ground depression of subway stations which is constructed in areas with dense buildings,heavy traffic or complicated pipelines are very strict,and PBA method has its unique advantages in this respect.The key factor of PBA method is ground depression.And it is of great significance to analysis and predict the ground depression which is caused by construction by adopting reasonable and scientific methods.And it is also be of reference value and guiding value to the construction of this project and similar projects.Based on the PBA method project of Dongbazhongjie Station of Beijing Metro Line 3,this paper mainly studies the following aspects:1.Based on the Engineering Geological conditions of Dongba Zhongjie Subway Station,the finite difference numerical simulation software MIDAS GTS NX,and the characteristics of PBA method,the finite element model is established to simulate the whole construction process of Dongbazhongjie Station.Comparison and analysis with construction monitoring data.2.This paper studies the depression law,the law of horizontal displacement and the internal force of steel tube column caused by excavation of pilot tunnel,construction of pile-column system,construction of arch,excavation of platform storey and hall storey.3.Through simulating the different excavation sequence of pilot tunnel,and analyzing the data.The optimal excavation scheme is proposed.4.Simulating the construction conditions of different steel pipe column spacing,and analyzing the data.The optimal pile spacing is proposed.