Study On Dynamic Response And Damage Of Cylindrical Shell Model Of Submerged Floating Tunnel On Underwater Explosion

Due to its advantages such as large span,little longitudinal slope,strong resistance to environmental interference,and green environmental protection,the submerged floating tunnel(SFT)has attracted rich attention at home and abroad in recent years.The underwater explosion(UNDEX)accidents may bring acute threats to the safe operation of SFT.This paper takes the dynamic response and damage of SFT on UNDEX as the research object and carries out the study from three parts of UNDEX load calculations,load-structure coupled on UNDEX,and numerical simulation of SFT on UNDEX.Through study,this paper verifies the theoretical calculation formula of UNDEX load,deduces the UNDEX load-structure coupled theory based on the reflected after the flow of virtual source(RAVS)method,establishes the two-dimensional and three-dimensional cylindrical shell model of SFT based on the Love shell theory and the SFT numerical model under UNDEX based on the ABAQUS acoustic-structure coupled algorithm.The dynamic response and damage of SFT on UNDEX are analyzed.The main conclusions as flowing.(1)The load-structure coupled theory based on the RAVS method can be used for the rapid theoretical calculation of the dynamic response of cylindrical shells on the UNDEX action and is closer to the exact theoretical solution.(2)The theoretical model of the two-dimensional cylindrical shell of SFT has a fast calculation speed,which can be used for the preliminary law analysis of the SFT on UNDEX.The three-dimensional cylindrical shell theoretical model of the SFT can calculate the tunnel response more accurately,which can provide a theoretical calculation tool for exploring the reasonable range of the SFT design parameters.(3)The SFT numerical model on UNDEX based on the ABAQUS sound-structure coupled algorithm can analyze the dynamic damage degree and distribution law of SFT under large-equivalent UNDEX,which provides a numerical calculation tool for the anti-explosion and explosion-proof design of SFT.(4)Scaled distance is a significant parameter that affects the UNDEX load.With the increase of the scaled distance,the maximum displacement of the SFT decreases in an inverse-proportional function;reasonable increase of the scaled distance can significantly reduce the explosion response of the SFT.(5)The tube length is a significant design parameter of the SFT.The influence of the tube length on the dynamic response of the SFT is related to the anchor cable action.In the case of considering the effect of the anchor cable,the maximum displacement of the SFT decreases with the increase of the tube length;without considering the anchor cable,the maximum displacement of the SFT increases with the increase of the tube length.(6)Under different UNDEX loads,the damage degree of the back blasting surface of SFT is greater than that of the front blasting surface,and the tensile damage degree is greater than that of compression damage.With the increase of explosion load,the damaged area of the SFT can develop from strip to sheet,from single existence to mutual connection,and the overall damage risk of the tunnel will increase.Through the study of the paper,a theoretical analysis tool for UNDEX dynamic response of SFT is established,the dynamic response and damage development law of SFT on UNDEX are preliminarily revealed,which can be used for the anti-blast and explosion-proof design of SFT and similarity underwater structure.