A Study On Influence Zoning Of Railway Settlement Durying Tunnel Construction Underpassing By Conventional Method

At present, China is on the target for the large-scale infrastructure construction, and transportation construction project is top priority, so our country has developed rail, road and subway transportation construction ambitionsly. A large amount of infrastructure will inevitably produce a large number of interchange projects of various lines, among which, the problems of various lines of under-cross railway will be very conspicuous. The traditional construction methods of under-cross railway lack forecast before construction (impact area) and active control in the process, which seriously afftects not only the normal railway traffic organization and transport capacity, but also local transport and economic development.Relying on the third phase project of Changchun Light Rail Transit Yatai Avenue to Puppet Manchurian Imperial Palace range, on the basis of summary and critical absorption, methods such as research, numerical analysis, field testing and experience in analog were used, and research on the particularity and universality of approaching excavation of the mined tunnel construction under railway were did. The main contents are as follows:1.Correlated theories and basical methods about approaching excavation in underground works were introduced.2.Through finite difference software Flac3D, the thesis established three-dimensional caculation model and get the result of subgrade settlement and track settlemet of single-hole or two-hole tunel under railway construction in the situation of different depth and spacing, and found the statistical relationship between depth and spacing.3.Through finite element analysis software Ansys, the thesis established static model of track-spring-subgrade, and studied the interaction of subgrade and track, as well as statistical relationship of the values of subgrade settlement and track settlement.4. According to the experience of railway maintenance and similar projects, based on displacement criterion, the thesis studied the coherent threshold (absolute settlement and the vector of track longitudinal irregularity) of zoning and by statistic mechanis, studied related indicators in expressions and put forward thezoning based on ration of depth (H/D) with geometric adjacent degree A.5. For newly built tunnel,3 grades construction parameters are studied and setted for different zoning. The rationality of numerical analysis andzoning is proved by onsite monitoring.6. Some research conclusions about the case and universality of mined tunnel under-cross railway were gained.The track studied in this thesis thesis is just ballasted track, and the eological condition is limited in soft ground like the third phase project of Changchun light rail transit from Yatai Avenue to Puppet Manchurian Imperial Palace. The influence factors only involved geometric adjacent degree and depth.