Shaking Table Test Study On Carbon Fiber Reinforced RC Frame Structure Under The Influence Of Mining Subsidence

China’s coal reserves are limited,and "three coal" accounted for a large coal.As the demand for coal resources increases,mining coal under buildings is inevitable in future development.At the same time,due to the heavy mining of coal has formed a lot of empty mining areas.The surface of the mining area may sink,resulting in adverse conditions of tilt,torsion and stretching of the surrounding buildings.China is a multi-earthquake country,80% of the mining areas are located in the seismic fortification areas.When an earthquake occurs,it will cause buildings to suffer from double damage from mining subsidence and earthquake.To avoid the huge economic losses and casualties caused by serious damage to the structure when this occurs,it is very necessary to find an effective way to ensure the safety performance of the building structure under the action of mining subsidence and seismic coupling.This article is based on the National Natural Science Foundation of China "Research on the Dynamic Instability of Rocks and the Safety of Buildings in Seismic Mining Areas".Based on the structural dynamics and similarity theory,two 6-story two-layers with a scale ratio of 1/10 were designed and produced.Two-span reinforced concrete frame structure,and one of the frame structures is reinforced with carbon fiber.In this paper,three working conditions are set up,and the frame structure is tilted at 2mm/m,4mm/m,and 6mm/m respectively;three types of seismic waves are selected: El-Centro wave,Taft wave and artificial simulation wave.Shaking table were tested under three operating conditions for two structures,Using theoretical analysis,experimental research and numerical simulation to explore its performance.the following results can be obtained:(1)When the two structures are tilted under three working conditions,the self-vibration frequency of the structure decreases.The maximum reduction of the reinforced structure is 5.1%,the maximum of the unreinforced structure is 7.5%,and the natural vibration frequency of the reinforced structure is smaller than that of the unreinforced structure.Under the same working conditions,the natural vibration frequency of the reinforced structure is higher than that of the unreinforced structure,with a maximum difference of 13.2.It shows that mining subsidence causes damage to the structure,and with the increase of inclination,the decrease of natural vibration frequency increases.According to the kinetic formula,the structural stiffness decreases greatly,and its seismic capacity is weakened.After carbon fiber reinforcement,the overall stiffness of the structure is improved,the degradation of the stiffness is delayed,and the seismic resistance of the structure is improved.(2)According to theoretical calculations,carbon fiber reinforcement improves the bearing capacity of the structure.During the test,the first and second layers of the structure were damaged first,the damage is serious and it is easy to form a weak area,the safety performance of the structure is reduced.After carbon fiber reinforcement,the inter-layer displacement angle and vertex displacement of the structure are reduced by up to 19.1% and 14.9% compared with the unreinforced structure.It shows that the inter-layer deformation and overall deformation of the reinforced structure are smaller,and the damage degree is lower than that of the unreinforced structure,improving the overall performance and anti-deformation ability of the structure,optimizing the structure ductility and improving the safety performance of the structure.(3)Energy dissipation analysis shows that the damping dissipation energy of the unreinforced structure is small,which is not conducive to the structure’s internal damping to dissipate seismic energy,and the damage caused by the earthquake is enhanced.The damping dissipation energy of the structure after carbon fiber reinforcement increases,up to 36.18% more than the unreinforced structure,which dissipates most of the seismic energy.The damage to the structure is reduced,and the earthquake resistance of the structure is improved.At the same time,it also reflects the effectiveness of carbon fiber reinforcement,which is conducive to the safety control of the building structure under the combined action of subsidence and earthquake.The paper has 26 drawings,15 tables,and 75 references.