Study On Connection Mode And Its Mechanical Properties Between Deep Subway Station And Its Entrance

As the development of shallow underground space in cities has been becoming more and more intense,more and more subway stations have been settting up toward deep underground.The cross section of the entrance and exit of a deep metro station belongs to a special type of cross tunnel.Due to the complex structure of the entrance and exit cross sections,there are special requirements for excavation methods,reinforcement of surrounding rocks,and monitoring measurements.This thesis takes the connection structure of the entrance and exit section of a single arch,double-deck,deep metro station in Chongqing as the research object,and systematically implements the system of deep and shallow burial of tunnels in large section subway stations in Chongqing,the structure optimization and reinforcement scheme for the entrance and entrance sections of the station,the construction scheme of the entrance and exit sections,and the construction process.The main work of this thesis is as follows:By summarizing and analyzing the connection form of deep underground subway stations and entrances and exits in Chongqing city,we have formulated the structure of the entrances and exits of subway stations in this thesis based on the theory of pressure arch,we have divided the deep and shallow burial tunnels of stations under Grade IV surrounding rock in Chongqing.Using the numerical simulation method,The Finite difference software-FLAC3 D is employed to study the initial support thickness and the reinforcement scheme of the surrounding rock at the entrance and exit intersections,and the stress state of the surrounding rock and the initial support structure was analyzed to determine the reasonable support and reinforcement parameters of the surrounding rock.Using numerical simulation method,The Finite difference software-FLAC3 D is employed to compare and analyze different construction planes at the station entrance and exit section,and selecting the optimal scheme,and the great method is adopted for the entrance and exit passages.The stress state of the surrounding rock during the construction of the scheme was analyzed.At the same time,the timing of the entrance and exit and the length of excavation of the core soil were discussed.Using the method of numerical simulation,the construction process of the inclined passage section at the entrance and exit of the station was studied by using The Finite difference software-FLAC3 D.The stress state of the surrounding rock and the initial support structure was analyzed,and the depth and slope of the influencing factors of the inclinedchannel were discussed.