Key Technology And Engineering Application About Underground Room For Shield Receiving

Urban transportation,pipelines,and buildings are becoming more and more dense so that it is increasingly difficult to meet the site conditions required for traditional shield receiving methods,which highly increases the risks,duration,and costs of a construction,and then it is a great tendency for shield receiving transforming from surface to underground.Among these solutions,the shield underground receiving room,equiped with the characteristics of economy,applicability,relative speed and small amount of waste,has the widely applicated prospects.The concept of shield underground receiving room derives from an engineering practice of shield receiving in the Line 14 of the Beijing Subway,and the relevant research and application are still rare.Based on this project,the paper mainly concentrates on the key construction technology of the underground receiving room and expands into two parts of work: numerical simulation and key technology.At the numerical simulation part,two times of construction processes were completed and analyzed by the settlement and reinforcement theory.The model was built by MIDAS and calculation was based on FLAC3 D.First,the construction process of the shield receiving room with general consolidation measures was simulated,and the effects of the mining section and the shield section were analyzed.The results shows that the increase of the mining section and the shield advancing at receiving stage has significantly aggravated the surface settlement of the corresponding section and adjacent areas.The superposition of the two constructions causes the section of the underground receiving room becoming the most severe section,and the adjacent area is next one.Secondly,it shows that under ideal construction conditions,the shield tunneling has little effect on the secondary lining structure of the receiving room built the mining method.The receiving influence is similar to that of ground receiving.Therefore,the ground receiving process design can provides large reference for receivie by the method of shield underground receiving room.Based on the above direction,the paper simulates the construction process of the shield receiving room with targeting reinforcement measures.The results show that the reinforcement measures have achieved the control of the construction impact,and the surface settlement,crown settlement,and the stress state of the secondary lining structure about the receiving room can meet the corresponding specification requirements.However,due to the influence of groundwater and the shield’ s attitude into tunnel portal,the simulation of the displacement at the end wall in this project has a larger deviation with the monitoring data.,which indicates that the strength of the tunnel portal needs to be weakened to a certain extent during the simulation,but there is no accurate simulation approach beyond the engineering conditions and reference to similar experience.Therefore,in the actual construction,it is still necessary to maintain highly attention on this site and control it by strengthening monitoring and emergency measures.Finally,the paper introduces the technical key and explicits the construction steps,connection design and waterproof design for the shield underground receiving rooming,and solves the problem of the jiont process about the linning structure.