Study On Structural Type And Mechanical Behavior Of Wellhole Underground Parking Lot

With the rapid advancement of urbanization in China,the problems of car parking and traffic congestion in urban areas have not been effectively alleviated.There is a huge contradiction between the rapid growth of automobile consumption and the parking spaces that are in short supply,and thewellhole underground parking lot series technology is a feasible solution.The main structure of the wellhole underground parking lot is composed of a circular structure exterior wall and a multi-storey parking annular floor connected with the wall body.This thesis analyzes the engineering characteristics of the wellhole underground parking lot and mainly analyzes the enclosure structure and the main structure of the underground parking lot.And research results are as follows.?1?First,the types of urban underground garages and their advantages and disadvantages are summarized.The concept,structure,system composition and work flow of wellhole underground garages are elaborated.The structure of wellhole underground parking lot and the distribution of vehicle berths can be seen.The access method is quite different from the traditional underground garage.It can make more efficient use of underground space and parking area.In addition,the circular enclosure structure can also more effectively utilize the compression resistance of concrete.?2?According to the characteristics of sand and gravel in Chengdu plain area,by comparing the characteristics and disadvantages of different enclosure structures,it is concluded that the use of row piles and frame-type enclosure structures is a more economic and reasonable support method;The lateral support stiffness can be effectively combined with the planar elastic foundation beam method to simplify the three-dimensional circular foundation pit as a two-dimensional problem.?3?Using FLAC^3D to simulate the excavation of the garage pit,analyze the internal force and deformation characteristics of the pile,canopy and ring beams in the excavation of the foundation pit,and combine the numerical analysis methods to the reasonable parameters of each important component?such as pile diameter,pile-end embedding conditions,diameter of foundation pit,etc.?are taken for analysis.?4?A structure-load model was established through ANSYS to analyze the stress characteristics of the main body structure of a wellhole underground parking lot during the construction phase and normal use phase conditions,and then to analyze the factors affecting the garage structure one by one.These factors include:Structural section stiffness changes?slab stiffness ratio,stiffness ratio of beam to column,stiffness ratio of wall to wall?,formation environment change?elastic foundation coefficient?,etc.