Research On Environment Impact And Influential Partition By Excavation In Suzhou Metro Pit Engineering

In recent years, subway becomes one of the most important ways to solve the urban traffic jam. Ordinarily, Subway lines cross through the city center, So how to control the deformation of subway foundation pit to make sure the security and usability of the surrounding buildings becomes one of the most important key technology and concerns civil engineers.The background of this research paper is based on a real construction project of Suzhou metro line 4. The numerical simulation and monitoring data statistical analysis have been conducted to study the impact of the subway construction on the surrounding environment, the different types of foundation form and the corresponding influence partition. The main research results are as follows:(1)The conditions of hydrogeology and engineering geology at the 80.0m depth under the Suzhou metro line 4 have been summarized. The hydrogeological structure of Suzhou metro line 4 is classified into 8 categories according to the space combination relationship of the foundation pit and water-resisting layer (or aquifer layer) as well as the difference of regional hydrogeological. The foundation pit of Suzhou metro line 4 is classifed into 5 categories according to the aquifer types in of foundation pit and the danger caused by aquifer at the bottom of foundation pit engineering as well as the impact of each type of foundation pit on surrounding environment.(2)The lateral deformation of retaining structure and the pit surface settlement form have been analyzed by numerical simulation combined with monitoring data statistics. The variation range, the average of the maximum lateral displacement of retaining structures and the pit surface maximum subsidence have been provided.(3)The typical foundation forms in Suzhou metro are summarized. The numerical simulation have been used to figure out the impact of the pit construction on different foundation types of buildings. The pit soil subsidence prediction curve is calculated by Rayleigh function. The impact areas, variation of surface deformation and mechanical characteristics of superstructure have been provided from the numerical results.(4)The GIS platform has been built to create visual model of hydrogeology classification of the Suzhou metro line 4 and the numerical simulation results. The soil layers of differernt hydrogeological structures, environmental impact of dewatering and water level isoline around the foundation pit have been visualized as well.