Study On The Damage Mechanism And Water Inrush Process Of Underwater Explosion Tunnel Structure

Underwater tunnels are playing an increasingly important role in transportation systems due to their great advantages in overcoming physical barriers and minimizing the impact on the local environment.Underwater tunnels may be damaged by terrorist attacks,accidental explosions,construction explosions and other explosive loads during their use,which may lead to sudden water disasters.Therefore,in this paper,the main line of research is to study the damage mechanism of underwater explosion tunnel structure and the sudden water process,carry out underwater tunnel explosion test,use ANSYS/LS-DYNA,near-field dynamics calculation method,FLUENT-EDEM coupling algorithm for modeling and analysis,study the dynamic response mechanism of box tunnel structure under explosion load,simulate the sudden water law in the damage area,discuss the advantages and disadvantages of different The advantages and disadvantages of different simulation software are discussed,and applicable suggestions are given.First,based on the theoretical study of the damage mechanics of underwater explosive tunnel structures,model tests of underwater tunnel explosions were carried out,and the dynamic response laws of concrete tunnel specimens under different emulsion explosive equivalents were compared by the dynamic strain monitoring signals of concrete model measurement points.According to the size of the measured damage range and the length of crack extension,the damage form of the box-type tunnel shrinkage model specimen under the action of underwater blasting load was investigated;the 1:1 modeling simulation analysis of the test was carried out by using the S-ALE algorithm and the near-field dynamics calculation method in ANSYS/LS-DYNA,and the simulation results were found to be basically consistent with the test results when compared with the test data and the damage form,which verified the The reliability of the two algorithms was verified,and the simulation results were further analyzed to obtain the complete process of propagation of the underwater explosion shock wave and the deformation law of the specimen structure;the statistical analysis of the measured point strain and displacement data revealed the dynamic response law of the box-shaped tunnel specimen under the explosion load.Secondly,a full-scale modeling simulation analysis of a lake bottom tunnel using S-ALE algorithm in ANSYS/LS-DYNA predicts the damage area of the tunnel under8 m water depth and 64 kg TNT contact explosion;based on the results of DYNA analysis,the FLUENT-EDEM coupling algorithm is applied to study the tunnel water burst process derived from the explosion damage.The calculation results reveal the process of tunnel sudden water: the tunnel structure is damaged under the blast impact load after the explosive explosion,the block particles in the damage area occur splash and bulge movement,and then the water medium under the action of gravity holds the broken block particles to the tunnel movement.