Numerical Simulation Analysis Of Mechanical Response Of Damaged Structure Based On Continuous-discontinuous Theory

"White to black" is a typical plan for the reconstruction of old cement concrete pavement in China.There are many cracks in the old cement concrete pavement after micro-crack regeneration treatment.These cracks have brought an important impact on the service performance of the pavement structure after "white to black".Considering the fact that the mechanical response analysis of asphalt overlay on cracked concrete pavement is very complicated,this article uses the numerical calculation method of coupling finite element and discrete discrete element based on the continuous-discontinuous analysis theory to break the evolution mechanism and mechanical load of damaged structure The performance and the selection of calculation parameters were studied.On this basis,the mechanical response of the cracked pavement structure was analyzed.The main research results obtained are as follows:(1)A numerical simulation analysis of the Brazilian split test process of homogeneous rock specimens was carried out to solve the random problem of meso-parameter selection in the traditional discrete element method.And a new calculation scheme is proposed by performing localized strengthening analysis on the calculation model based on the local stress concentration phenomenon,which can realize the direct application of macroscopic mechanical parameters to the numerical simulation analysis of meso-fracture.(2)To study the fracture evolution mechanism and mechanical bearing performance of damaged concrete structures,the numerical calculation method of mutual exchange of finite elements and discrete particles is used,the numerical simulation analysis of the Brazilian split evolution process and mechanical load-bearing properties of uniformly distributed joint shale disc specimens,the effects of different joint angles and material strength on the fracture process were studied,and the rationality of the simulation analysis results is verified through comparative analysis with the test results in the literature.(3)For a typical pavement structure,the numerical method of coupling finite element and discrete particle unit is used for calculation and analysis and compared with the calculation structure of traditional finite element method,therefore the calculation effect of the coupled algorithm in the calculation and analysis of continuous structural mechanical response problems is verified.It provided a reference for establishing a calculation model for the analysis of the mechanical response of damaged pavement structures through the analysis of the influence of different pavement model sizes and boundary conditions.(4)For cracked pavement structure after homogenization treatment of pavement micro cracks,the discrete element is used to simulate the crushing structure that can squeeze each other,finite element simulation of continuous overlay and cement stabilization structure,to study the mechanical response of cracked pavement structure.The effects of different crack widths and crack angles on the mechanical properties of the overlay structure are analyzed,which provides a certain technical basis for optimizing the construction process and quality control standards of cement concrete microcrack homogenization.