Deformation Characteristics of Surrounding Rock in Shallow-Buried Super-Large Span and Small Clear Distance Stations in Inclined Strata

Focusing the lack of experience regarding surrounding rock deformation characteristics, construction methods and process arrangement for the shallow buried super-large span small clear distance subway station crossing sandstone mudstone interbedded inclined stratum when the of alternating sandstone and mudstone, this study takes the Ciqikou Station project on Chongqing Rail Line 27 as a case study, the different stratum inclination conditions under the influence of the excavation sequence and method of the stability of the station surrounding rock are explored. The preferred construction method of the shallow buried super-large span small clearance subway station crossing sandstone mudstone interbedded stratum is proposed. The results show that: In sandstone inclined interbedded strata, the inclination angle of 40° is the critical threshold of construction sequence, when the inclination angle of the strata is less than 40°, the side chamber passing through the inclined strata should be excavated first; When the inclination angle is more than 40°, excavating the side chamber away from the inclined strata can significantly reduce the deformation of the surrounding rock and settlement, among which, the double sidewall guide pit method as the preferred method can significantly reduce the deformation of the surrounding rock compared to the CRD method, and the CRD method can also significantly reduce the deformation of the surrounding rock. Optimizing the support structure force, which has good applicability under the project conditions.