针对浅埋超大跨小净距地铁车站穿越砂岩泥岩互层倾斜地层时围岩变形特征、施工方法及工序安排无经验可依的难题,以重庆轨道27号线磁器口车站工程为依托,探讨了不同地层倾角条件下开挖顺序和方法对车站围岩稳定性的影响,提出了浅埋超大跨小净距地铁车站穿越砂泥岩互层地层围岩优选施工方法。结果表明:在砂泥岩倾斜互层地层中,地层倾角40°为施工顺序的临界阈值,当地层倾角小于40°时,应当先开挖穿越倾斜地层侧洞室;当倾角大于40°时,先开挖远离倾斜地层侧洞室能显著降低围岩变形沉降,双侧壁导坑法作为优选工法较CRD法能显著降低围岩变形且优化支护结构受力,在该工程条件下具有良好适用性。
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 theof 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.
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