Study On The Influence Of Excavation To Adjacent Existing Tunnels In Sandy Silt Area

With the rapid development of China’s economy and the city modernization, the demand for space is growing, especially in the big cities, the conflict between limited land resources and the growing demand has been a great problem. To solve this problem,people began to seek space from aerial and underground, so a lot of high-rise buildings and underground structures appeared. With the develop of the metro system, and the subsequent construction excavation must consider the impact on the surrounding environment, particularly sensitive tunnel, excessive deformation will inevitably lead to damage to existing tunnel. Contrapose the influence between the excavation in sandy silt area and existing tunnel, the contents include:(1) According to the papers and related data, this paper has analysed the east city sandy silt deposition regularity and characteristics.(2) Using the experience of research and engineering geological exploration data gives a preliminary HS model parameters of sandy silt. According the numerical geotechnical simulation test and the results of laboratory geotechnical test corrected the HS model parameters, then joined the small strain parameters on the revised HS model parameters, got the sandy silt HSS model parameters.(3) Using the determined sandy silt HSS model parameters and Plaxis to model the influence of deep foundation pit excavation on adjacent existing tunnel. Compare with the result of actual meansurement analysis the applicability and the scientificity of the modeling result. Finally the HSS each part parameters respectively increased by 2% to analysis the sensitivity of sandy silt HSS model parameter.(4) On the basis of modeling results, changing the tunnel buried depth, the horizontal distance, and precipitation depth of foundation pit, analysing the effect of these factors on the deformation of excavation, exploring the mechanism of the influence of excavation on adjacent existing tunnel.