Study On Surrounding Rock Deformation Of Subway Station Tunnel Group In Semi-diagenetic Strata

This paper combines the complex underground excavated platform tunnel group project of Qingxiushan Station of Nanning Rail Transit Line 3,the numerical simulation software MADAS / GTS is used to establish a three-dimensional numerical model,and studies the changes in the stress field and displacement field of the surrounding rock of the underground excavated tunnel group under different construction methods Law,choose a most suitable construction method,verify the rationality of the construction method in combination with on-site monitoring data,and study the construction sequence between inclined escalator passages and shafts.Based on this,the main line tunnels,horizontal passages,inclined escalator passages in the tunnel group and the interaction between shafts are studied.The specific research is as follows:(1)The finite element software MADAS / GTS was used to establish a three-dimensional numerical model of the underground tunnel group at Qingxiushan Station.The stress field and displacement field of No.2 and No.3 horizontal channels under different construction methods were analyzed and studied.In semi-diagenetic strata A suitable tunnel construction method is the three-step method,and the field monitoring data of the No.2 and No.3 cross-channel lining structures are compared with the numerical calculation results of the three-step method to verify the rationality of the tunnel construction method.(2)By changing the construction sequence between the inclined escalator passage and the two shaft passages,analysis and study on the change law of the surrounding rock stress field and displacement field caused by the mutual influence between the inclined escalator passage and the shaft passage,it is found that the No.3 shaft and No.4 shaft are constructed first The inclined escalator passage has little influence on the surrounding rock of the tunnel.(3)After determining the reasonable construction sequence of inclined escalator passages and shafts,on this basis,the stress field and displacement field of surrounding rock produced by the interaction between the inclined escalator passages and shafts are studied,and the research and analysis are also carried out.The variation law of the stress field and displacement field of the surrounding rock produced by the mutual influence between the inclined escalator channel and the horizontal channel and between the main tunnel and the two shafts.