Research On Construction Technology Of Shield Tunneling In Complex Soft Environment Under Soft Water-bearing Stratum

With the rapid advancement of urban subway construction in China in recent years,the technical problems of subway tunnel shield tunneling under complex environment have become increasingly prominent.The paper takes the Tianjin Metro Line 6 Black Niucheng Road Station ~ Meijiang Road Station ~ Zuojiang Road Station ~ Meijiang Scenic Area Station as the background,according to the special site conditions of the project and the characteristics of the soft water-bearing stratum,the soft under complex environmental conditions Research on shield tunneling technology in water-bearing strata,the main research and achievements are as follows:(1)Aiming at the impact of the shield tunnel construction of Tianjin Metro Line 6 on the existing railway construction,a reasonable and feasible shield tunneling construction scheme in the soft water-bearing stratum is proposed.The numerical simulation method was used to analyze the tunnel construction under the shield tunnel,and the maximum settlement and elevation of the ground surface were controlled within the design value range.Through numerical simulation,a reasonable grouting scheme and reinforcement measures for on-site construction are proposed.According to the on-site monitoring data,the analysis and effect of the shielded under-operated railway control are analyzed.(2)Aiming at the problems encountered in the construction of the communication channel in the water-rich soft soil layer of the tunnel in this project,a scheme combining the freezing method in the tunnel and the excavation of the mining method is proposed to improve thestrength of the soil to resist the soil.Body pressure,while reducing soil permeability to isolate groundwater.Aiming at the construction scheme combining the freezing method in the tunnel and the excavation of the mine method,the quality control measures of the freezing hole drilling,earth excavation,waterproof layer laying and concrete pouring are put forward,and the noise and dust generated in the on-site construction are proposed.The corresponding environmental protection measures have been formulated for the sewage waste problem to ensure the smooth progress of the construction of the communication channel.(3)In the case that the receiving water at the receiving end is rich in water pressure,in order to reduce the risk of the traditional receiving method,a secondary receiving scheme is proposed,which effectively improves the safety of the shield receiving technology under complex geological conditions.According to the special geological conditions of this section,the traditional arrival segment receiving scheme is optimized,and the steel sleeve auxiliary receiving scheme is proposed,which improves the construction safety and achieves good results.