Study On Mechanical Parameters Of The Reinforced Ground And Mechanism Of Ground Surface Settlement Induced By Mining Method In Shijiazhuang Subway Tunnels

The mining method has been widely used in the subway construction all over the country.When it comes to the project in Shijiazhuang,although the process of designing subway tunnels is always taking examples by similar design experience in other domestic city,there is still a lack of mature technology and experience for the design and construction in the region.Especially for mining design and construction of anhydrous sand,which is far more less in the domestic cities.In addition,there are few studies on the inverse analysis for shallow buried tunnel formation parameters.Based on the above analysis,the paper put forward the value methods of formation parameters for the large section mining method construction on the basis of the subway construction and the specific formation in Shijiazhuang.Furthermore,the law of ground subsidence of the shallow buried excavation in Shijiazhuang has been studied.(1)Stratigraphic performance indicators have been accumulated.During the investigation report of the project and collection of some related engineering exploration data,a series of formation performance index have been gotten via the method of mathematical statistics.Among the process of handling data,in order to lay a solid foundation for the analysis of numerical calculation model,sand formation parameters were being recorded particularly.(2)The formation parameters have been analyzed inversely.By using numerical simulation software to finish modeling according to the formation parameters sorted out by date disposal.Based on the sensitivity analysis of the parameter with the data measured between Liu-Huo,selected the parameters which can be adopted by inverse analysis.Then the parameter after inverse analysis have been put into the model to calculate settlement values at the earth's surface and coMPared with the measured values to figure out the error as well as judged the effect of the results of inverse analysis.(3)The influence of the surface subsidence caused by buried depth and formation situation has been studied.Based on the parameter inverse analysis,during the excavation of horseshoe section tunnel,the surface subsidence trough curve and related parameters about buried depth and different stratum are figured out by means of numerical simulation.(4)The law of ground surface settlement induced by different mining methods has been studied and analyzed.With the background of Xiao-Xi section,during the process of modeling under different construction methods,the surface subsidence curve and it'sinfluence scope as well as the maximum surface settlement in the stage of excavation of each pilot tunnel are figured out respectively.