Study On Reasonable Excavation Methods And Optimization Of Structural Parameters Of Subway Station By Open-cut And Undermining Of Soil And Rock Stratum

The design feasibility and advantages and disadvantages of cover and excavation top-town method and shallow tunneling method of May 4th square station was preliminarily discussed, May 4th square station in Qingdao as engineering background, combining the metro line 3 overall design and the related geological exploration materials. With stability analysis of the surrounding rock and supporting structure, optimization of related parameters, it further explored the design feasibility of open-cut and undermining methods of May 4th square station by ABAQUS.The main research work could be summarized as follows:⑴With the shear strength reduction the safety factor of two kinds of construction conditions of the surrounding rock was given: cover and excavation top-town method design for 1.49236; shallow tunneling method design for 2.765. Judging from the simulation results, both the design schemes could meet stability requirement.⑵Through optimized simulation of pile foundation parameters of design, with comparative analysis of the surface subsidence, the stability of palisade structure and main structure, while reducing the pile foundation deep 2 meters, the surrounding rock and structure could ensure the stability, the safety factor for 1.45.⑶Combined with the orthogonal design, the sequence of the factors affecting the stability of surrounding rock was buried depth, lining strength, the stress release rate. With the specific analysis results, scheme 8(stress release rate for 20%, lining strength for C35 (2%), buried deep for 23.73 meters) was considered as the best scheme of the orthogonal design, the safety factor for 1.69.