Study on Settlement Law of New PBA Station of Beijing Metro in Silty Clay Stratum
The PBA(Pile-Beam-Arch)construction method has become the mainstream technology for underground excavation of subway stations in bustling sections of Beijing.However,due to its complex process transformation and multiple construction steps,it is prone to geological settlement.The new PBA construction method is based on the single-layer 4-guide hole PBA method,combining the middle guide hole and sharing the middle partition wall to form a large cross-section guide hole constructed by the CD(center diaphragm)method.Compared to the traditional double-layer 8-lead PBA method and the recently promoted single-layer 4-lead PBA method,it is difficult to grasp the law of geological subsidence.Based on the Ganluyuan Station of Beijing Metro Line 22,finite element numerical analysis software is used to simulate the construction process of the station.Combined with on-site measured data,the settlement law of the new PBA station in the silty clay layer is analyzed.The results show that the maximum settlement during the construction process of the new PBA station in the silty clay layer occurs above the arch of the excavation surface;Ground subsidence mainly occurs during the excavation and arching stages of the pilot tunnel,accounting for approximately 89.5%of the total subsidence.Due to the influence of the form of the pilot tunnel,the geological settlement caused by the construction phase of the pilot tunnel is greater than that of traditional PBA stations.
silty clay stratumstratum settlementnew PBA(Pile-Beam-Arch)stationmetro station
万方数据
维普
