Damage Mechanics Model And Numerical Simulation Of Lining Concrete Based On Acoustic Emission

Tunnel engineering is one of the most important research fields in geotechnical engineering.The complexity and uncertainty of tunnel engineering lead to the evaluation of stress performance and stability of tunnel supporting structure as a major problem in engineering field.In this paper,through the combination of laboratory test,theoretical analysis and numerical simulation,the mechanical properties of the supporting structure materials of the Wuhan Yangtze River tunnel are studied.The main research work and conclusions are as follows:（1）Concrete uniaxial compression combined with acoustic emission synchronization test,concrete Brazil splitting test,concrete shear test,concrete routine three axis test and so on,the physical and mechanical parameters of concrete are obtained.Based on the emission rate of acoustic emission energy,the damage variable is put forward,and the quantitative description of the damage variable can be made to describe the degree of destruction of the sample during the test.（2）Combining with the mechanics of continuum medium,the stress-strain relationship model of uniaxial compression/pull damage of concrete is established.In order to facilitate the study and calculation,the stress-strain relationship model of concrete uniaxial elasto-plastic damage is simplified.Through comparison with the specifications and relevant literature,the damage variable can use an empirical expression,the damage variable defined in this paper and the damage variable in the specification.The change curve fits well.（3）In order to calibrate the peak post section of the stress-strain curve,based on the data obtained from the tests conducted in this paper,combined with statistics of domestic and foreign scholars’data,the related parameters(f_c,r,?_c,r,f_t,r,?_t,r and?_c)are further analyzed and the uniaxial compression/pull bullets established in this paper are established.The plastic damage model is compared with the research results of various scholars,that can prove the accuracy and applicability of the stress-strain relationship model.（4）Based on the mechanical parameters of the support material obtained by the test,through the setting of different stress conditions,using FLAC^3D software,the numerical simulation of the tunnel support structure was carried out.The mechanical properties of the tunnel support structure and the stability of the support structure were analyzed.