Experimental And Finite Element Simulation Analysis Of Dynamic Strength Of Tunnel Structure With Cracks

Tunnel structure is widely used in our traffic construction,but cracks will inevitably appear in the construction process.In the long-term use process,the cracks in the tunnel structure will crack,expand and penetrate,which will affect the service life of the tunnel,and will also have a certain negative impact on the stability and safety of the tunnel.Therefore,it is of great significance to study the crack growth in tunnel structure.There are many kinds of cracks around the tunnel structure,and the location and length of the cracks have different effects on the tunnel structure,so it is necessary to explore the influence of the length and location of the cracks around the tunnel on the crack growth in practical engineering.In the past,the research focused on the crack growth of the tunnel structure under static load or impact load,while the research on the crack growth of the tunnel under fatigue load is less,which needs further research.The main research method of this paper is to simulate the crack growth of tunnel structure by finite element method.In this paper,ABAQUS is used to establish the tunnel structure model with initial cracks,and the crack growth process is simulated by the joint calculation of FRANC3 D and ABAQUS software.Based on the model of concrete tunnel structure,the propagation of initial crack with different length and different position under fatigue load is simulated.The life of crack propagation in tunnel is calculated by Paris formula,and the stress intensity factor at crack tip is calculated by M-Integral method.The influence of different initial crack length and crack location on tunnel life and stress intensity factor at crack tip is analyzed.The results show that the smaller the crack arrest phenomenon is,the more obvious the stress intensity factor is.In order to better simulate the actual project,the propagation process of the tunnel crack under the fatigue load when the asphalt pavement is a multi-layer structure is calculated,and the life of the tunnel crack propagation is obtained,and the stress intensity factor at the crack tip is calculated.The influences of crack length andlocation on tunnel life and stress intensity factor are analyzed.The results show that the different initial crack length has little effect on the crack failure at the early stage of crack growth,and the effect increases gradually with the crack growth.