The Application Research Of Micro-settlement Control Technology In Underpinning Engineering Of Tunnel Through The Existing Subway Line

Along with the development of urban rail transit construction, the situation of new tunnel through existing railway tunnel is getting more and more. To ensure the smooth construction through existing subway line, it's necessary to adopt some measures to reinforce and underpinning construction of existing subway line. In order to ensure the safety traffic in construction operation, the existing lines on the deformation control standard is very strict. And it can't achieve this standard to depend on some traditional underpinning ways. The main technical problem is how to control and adjust the settlement of the existing railway, in order to satisfy the requirement of safe driving lines.Synchronous lifting control technology has be use to buildings moving and lifting or large components hoisting at first. With the development of hydraulic technology and computer technology, the field of application of this technology has been more widely. At the construction of new tunnel through existing railway, when synchronous lifting control technology has been used in underpinning construction, it's possible to control and adjust the settlement of the existing railway.This paper summarizes the design and construction of the project of the Dongzhimen station of Beijing Airport Subway line through the turn-back segment of the line 13. And discuss the hole-pile underpinning technology. The piles, beam and broad was component the system underpinning construction and effectively to underpinning existing line. Research the method of the existing structure adjustment micro-settlement through the synchronous lifting hydraulic control system.Base on the monitoring data of the turn-back segment of the line 13 in underpinning engineering, this paper analyzes the sedimentation characteristics of the existing railway structures during the engineering of the new tunnel through existing railway tunnel. And based on the monitoring data of adjustment micro-settlement, obtained the deformation rule of structure and rail when it use synchronous lifting hydraulic control technology to adjust of the existing railway structure. The results show that: (1) The factors of influence settlement more complex in the engineering of new tunnel through existing subway line. (2) The settlement joints is weak links and apt to cause the differential settlement. (3) It's effectively to adjust the settlement of existing lines using synchronous lifting hydraulic control technology.