Research Of Safety Impact Assessment Of Existing Subway Construction Nearby Underground Project

China's deepening urbanization nowadays drives the rapid development of large and medium cities. Because of demands for urbanization, construction of subway also enters into a period of rapid development.14 subway lines have been put into operation in Beijing at present, and have formed the subway operation network. The subway facilities the urban residents'trip and eases the urban traffic pressure while it also causes the problems as followings:the first problem is that formation of subway network will inevitably generate many intersected nodes, and the intersection between the existing and old structures has been an unavoidable problem for line planning, and the second problem is that rail transit structures are distributed in most of underground areas with continual development and utilization of underground space, and construction of the new underground project will affect the existing subway structure and safe operation. Therefore, it is urgent to carry out the safety assessment study on the existing subway affected by new underground project.This paper, through theoretical analysis, empirical statistics and numerical simulation, carries out the assessment study on safety of existing subway affected by of underground project from mechanics principle, affecting factor and pattern, and the following work has been conducted:1. Carrying out the preliminary analysis of impact of stress state and soil mass solidification of underground project construction on existing subway on the basis of thoroughly learning the theoretical knowledge of mechanics, rock mechanics and tunnel mechanics from the principle of disturbance of construction on stratum;2. Starting with theoretical study from new project condition, site hydrogeological and existing subway structure to analyze factors in which the underground project construction affects the structural deformation of subway, and carrying out the preliminary classification for the effect of factors;3.Collecting previous safety assessment information of nearby construction, carrying out the correlation analysis for some factors and existing structure deformation result with statistics correlation analysis principle and statistics package for social science (SPSS), and finally getting the impact assessment of single factor on structural deformation of existing subway;4. Studying the structural deformation pattern of existing subway for the common nearby construction conditions with numerical simulation method and ANSYS, and taking the displacement standard as study basis to complete demarcation of area affected on existing subway structure by new underground project in various conditions through analysis of deformation;5. Detailing the control measures of nearby construction on existing structural deformation combining with previous project experiences and maintenance measures on safe operation adopted by subway operation company.