The Elasto-plasticity Damage Evolution Mechanism On Surrounding Rock Of Tunnel With Excavation Stress

This paper is based on Ministry of Transportation and Communications Technology Project "Forecasting theory and warming systems on relaxation load of highway tunnel"(200631874024) ,holding the main line about the elastoplastic damage of surrounding rockets, By the ways of numerical simulation to study the elastoplastic damage with tunnel excavation in the process , through study on other aspects ,such as:the deformation of the tunnel, stress distribution and plastic zone of the scope, size ect, to analyse the elastoplastic damage of the tunnel in excavation at the uninstall process,and list the discipline in the whole process. The maining study reads as follows:(1) Combine Damage Mechanics and several damage detection methods for the tunnel, introducing the application on the damage theory in the rock-like materials (including rock tunnel) ,expounding the research status of the damage variable , as well as the definition of damage variable of the the tunnel.(2) Compare the failure mechanism the rock with the surrounding rockets of loading and unloading damage in the processing of excavation, confirming the major research object,which is the elastoplastic damagein withing Excavation unloading; simultaneously, in accordance with the tunnel under the rock damage mechanics theory and experience of existing unloading status, combined with energy dissipation theory, analysing the elastoplastic damage constitutive model which the energy dissipation is consided, then,get the revised damage evolution equation.(3) Using finite element analysis software-ANSYS10.0, to analyse classâ…¡toâ…£surrouding rockets,also,withing the help of BP Artificial Neural Network, Optimize the post-excavation disturbance zone and the mechanical parameters of rock bolting optimization parameters composity. simulate the unloading process of tunnel excavation practically, through analysing some aspects,such as:surrounding rockets displacement, stress, strain and plastic damage,obtained the elastic-plastic damage evolution law in the process of excavation tunnel.(4) Combined the finite element analysis of BiCheng Tunnel with the actual Monitoring data of BiCheng Tunnel, the elasto-plastic damage constitutive model is validated.The results show that the use of elastic-plastic damage constitutive model in this papar is fitted the actual project, it could be a reflection of the real tunnel excavation process of elasto-plastic damage evolution process, and it will be a higher guide on the actual project.Main innovations are shown as follows:(1) Combining the characteristics of tunnel construction, the introduction of energy dissipation which is based on the theory of elastic-plastic damage constitutive model, and optimize the damage evolution equation.(2) Based on BP Artificial Neural Network, inverse the rock mechanical parameters of the dynamic construction processing.As this,it can be used in the next construction step-by-step dynamic parameters, it reflect the change of rock mechanical parameters withing the the process of excavation.