Research On Cracks And Temperature Stress In Mass Concrete Structure Of Metro Station

The cracking of concrete structure in metro station affects the safety and service life of the structure.How to effectively control the temperature cracking of concrete,reduce the repair cost and reduce the loss is the key and difficult point in the construction.Based on engineering practice and numerical simulation method,this paper makes a detailed analysis and in-depth study on the cracks and stress distribution characteristics of concrete structure of Metro station.Firstly,the concrete cracks of two metro stations on Xiamen Rail Transit Line 2 are analyzed,and the distribution law of the cracks in the side wall of the metro station is explored.The temperature,stress and strain of the concrete structure of the metro station are monitored,and the variation law of the temperature and strain of the concrete structure with time is explored.Then,based on the relevant monitoring results,the temperature field and temperature stress field of the side wall are numerically analyzed by means of the finite element software ANS YS.In the simulation,the material nonlinearity and concrete deformation and cracking are taken into account,and the effect of interface restraint between new and old concrete on temperature stress of concrete is also considered.Based on the engineering practice,the parameters of adiabatic temperature rise of concrete and the boundary restraint strength of the side wall model are parameterized,and the idea of optimization and improvement is put forward.In addition,the influence of water pipe cooling on temperature field is considered in the simulation,and the effect of water pipe cooling is analyzedThen,the temperature stress of the roof of section 8 and 9 of Xinyang Avenue Station is analyzed,and the temperature stress field of adjacent roof is simulated.In addition,considering that cracks still occur and propagate in the roof after 28 days of pouring,the influence of ambient temperature on the temperature stress of the upper and lower surfaces and the interior of the roof is taken into account in the numerical simulationIn addition to analyzing the stress changes caused by temperature load,this paper also considers the influence of soil around and at the top of the station on the stress of the station structure,and puts forward the key points for crack prevention of concrete structure of the subway station.Finally,the calculation methods of concrete temperature stress and jumping length in the mass concrete construction program are summarized,and the calculation software of concrete jumping method construction is developed based on python.