Research On The Impact And Security Technology Of Urban Shallow Buried Tunnel Through The Existing Structures

In recent years, due to the rapid growth of urban traffic, shortage of urban land, high utilization of land and other reasons, the tunnel engineering approaching existing structures carried out in large numbers, endless variety of technical problems. Recent approaching projects compared to the past, not only large on scale, but the distance between the existing structures is smaller. We should launch the research combined with the city’s own characteristics.In this paper, the research carried out based on The Guanhui intercity railway. The Guanhui intercity railway is located in the Yangtze River Delta, its tunnel surrounding rock is mainly consist of saturated sand layer, the level of surrounding rock is Ⅲ to Ⅵ. The Guanhui intercity railway7project passes through multiple houses with dense and passes through existing railways5times. Firstly, this paper made an investigation and study on research status at home and abroad about urban shallow buried tunnel passing through existing structures. And then using numerical simulation and model test method, did the impact study of tunnel passing through existing structures. Finally put forward the safety control measures under the complicated condition. The specific work is listed in the following points:(1) Through the domestic and foreign research about tunnel passing through the existing structures, and combination with engineering characteristics of Guanhui intercity railway7project, we did the research about construction methods, supporting parameters, displacement and stress of structure when urban underground engineering passing through existing structures, and analysis the impact preliminarily.(2) According to the actual situation of engineering, we selected typical saturated sandy soil layer of Guanhui intercity railway7project, and established numerical simulation model, analyzing the influence that urban tunnel passing through the existing buildings and railways.(3) Selected typical cross section of Guanhui intercity railway7project, we carried out the laboratory model experiments, and analyzing the displacement of rock feature points and building monitoring points.(4) According to the field monitoring data, combined with the results of numerical calculation and model test results, assessing the influence that passing through existing buildings and railways. Finally, put forward the safety control measures of constructing urban shallow buried tunnel under complicated conditions.