The Application Research Of Active Underpinning Technology In Existing Lines Reform

Along with the development of the continuous intensification of urban and large-scale underground space, many cross-project and project-by proximity will adopt underpinning technology. The technology has very great significance, because it can be effective based on the actual situation to design and adjust construction programs to completed safety construction on the assumption of the Existing lines of normal operations smoothly. The widespread use of Underpinning's technology has played a positive role in the construction of environmental and the process of saving society in our country. However, in the various underpinning projects, the pile underpinning in the complicated geological conditions is the most difficult. it involves many structural problems and geotechnical problems, the complexity is greatly harder than general civil engineering. In addition, how to complete the underpinning project well, especially in the face of very strict requirements of settlement and uninterrupted operation of existing lines case, is a major problem. So we have to take a special study.This paper introduce current situation of current situation and typical projects and details of the hydraulic synchronizing PLC control, monitoring system in the use of information and the construction of the role.This paper summarizes the underpinning project of the light railway of region of Binhai in Tianjin, made the design about active underpinning and the construction in the alteration of the exiting lines ,made a situ soil test about long bored pile. At the same time, made use of PLAXIS software to frame finite element model. do a comparative analysis about the results between the ,in situ soil test and the theoretical calculations. In addition the stress state of pitch point had be calculated, the state of load shift when the exiting cluster was cut and the endogenous force had be anslysed.Through the compare between actual data that underpinning pile settlement data, the data about underpinning beams curve ,the changing curve of the two pier and light rail linear data from fabricating yard and theoretical arithmetic, the feasibility of active underpinning design in the project was be tested.