The Mechanical Performance Study And Influence Factors Analysis Of Large Open-hole Structure Of Subway Station

With the rapid development of China's economy and the continuous progress of urbanization,subway becomes an important way to ease traffic pressure in large and medium-sized cities.To meet the needs of construction operations during the construction of the subway,the floor of the station will be reserved for different sizes of open-hole,the stiffness of thick plate is seriously weakened by large size openings.There are obvious difference in design calculation between the large size of holes portion and general structure in subway station.However,most of the researches on the structure of underground stations are concentrated on the internal forces of conventional structures,there is also a lack of depth and meticulous research on the reserved subway station.Based on the static loading test and finite element simulation,the mechanical behavior and the factors affecting the mechanical performance of large open-hole structure of underground subway stations are studied and analyzed in this paper.Taking an underground station in Chengdu as the engineering background,designing two 1:10 scaled specimens for static loading test.Measure and analyze the load,strain and displacement of the test specimens,and observe the crack development of the test specimens.Study force performance of large opening-hole structure of subway station,and the effect of adding steel on the structural stress and deformation of the large-open-frame longitudinal beam.The results show that the addition of steel can effectively reduce the displacement of the longitudinal beam and the side wall,improve the bearing capacity of the structure,control the crack of the structure,change the distribution of the structural stress,and do not affect the use space of the structure.Based on the test,using finite element software ABAQUS established a three-dimensional load-structure model.The influence of factors such as the depth of support piles,the spacing of supporting piles,the stiffness of the continuous wall,and the distance between the columns and columns on the stress and deformation of the structure under the maintenance system of the retaining pile and the underground continuous wall are analyzed.The results show that the internal force and displacement of the main structure decrease with the increase of the depth of the retaining piles in a certain range,it has little impact when it goes beyond this range.With the increase of supporting pile spacing,the horizontal displacement of the structure increases,but the magnitude of the increase decreases,and finally tends to be stable.The increase of the stiffness of the continuous wall can effectively reduce the lateral displacement of the main structure and reduce the equivalent stress of the main structural member of the main structure.The horizontal displacement and stress of the structure can be reduced effectively by adding the wall column to the large open-hole structure.The wall column has little change in the use space of the structure,and it can play an effective strengthening effect.