Research On Structural Design Of Assembled Shaft In Sandy Mudstone Stratum

In recent years,China has made continuous development in infrastructure and social economy,many cities have the conditions for large-scale construction of subway projects.Compared with plain cities,due to the large fluctuation of pavement elevation in mountainous cities,it is inevitable to bury subway stations deeply.Under this condition,shafts need to be used as auxiliary works for construction.In order to take into account the construction channel and the starting operation of shield machine,the ultra deep and large section shaft structure came into being.Compared with the traditional drilling and blasting method,the full face mechanized tunneling method has been gradually popularized because of its high construction efficiency and little impact on the surrounding environment.Based on the above reasons,in order to further improve the construction efficiency and accelerate the process of engineering standardization,it is of great significance to study the structural parameters of prefabricated shaft lining.At the same time,compared with other underground structures,the shaft structure will be more affected under the action of earthquake because of its long tube shape.In order to ensure the safe operation of shaft structure and reduce earthquake damage,it is very important to clarify the dynamic response law of shaft under ground motion load to guide the structural design.Based on the shaft project of Chongguang station of Chongqing Metro Line 15,using the methods of literature investigation,theoretical analysis and numerical simulation,this paper studies the structural design parameters and seismic dynamic response law of fabricated shaft in sandy mudstone hard rock stratum.The main conclusions are as follows:1.Through the combination of literature research and numerical simulation,the applicable conditions of different shaft section forms are given,and the optimal structural section form of deep and large fabricated shaft in sandy mudstone stratum is determined.2.Through the combination of data investigation and theoretical analysis,the calculation theory of shaft wall load suitable for deep and large shaft in sandy mudstone stratum is deduced,and the theory deduced in this paper is further modified and optimized by numerical simulation considering the stress release rate.3.Through the combination of data investigation and numerical simulation,the design parameters of deep and large fabricated shaft structure suitable for sandy mudstone stratum are put forward.4.Using three-dimensional dynamic finite element numerical simulation method,the dynamic response law of fabricated shaft structure under seismic load is studied,and the dynamic response of shaft lining with different assembly forms under earthquake is compared.On the basis of considering the seismic response law,the design parameters of fabricated deep and large shaft structure in sandy mudstone stratum proposed in this paper are optimized.