Numerical Simulation Of Dynamic Instability Of Roadway Surrounding Rock Based On HJC Strength Criterion

Rock burst is one of the most prominent mine dynamic disasters in coal mining,which is a serious threat to coal mine safety production and has caused huge economic losses.But for the numerical simulation analysis of the tunnel stability under the condition of rock burst,the static constitutive relation can not understand the failure mechanism of surrounding rock.This paper focuses on the analysis of Yima Yuejin Coal Mine 25110 working face of Qianqiu mine and 21032 air rise concrete impact event case,Through the theoretical analysis and numerical simulation method,the paper studies the response law of surrounding rock under blast pressure.Theenergycriterion of rock burst is put forward,which provides a new way for prediction of rockburst in coal mine.For the Yuejin Mine coal company in 25110 working face,the future mine 21032air rise field impact damage condition,Combined with the microseismic monitoring data,analysis of the causes of high energy events and spectral characteristics of rock burst.By using the fast Fu Liye transform(FFT)method,the spectrum characteristics of rockburst in the two mines are analyzed,The results show that the low frequency components of ground pressure under the impact of the mainshock and a larger proportion of frequency are mainly distributed in 5~50Hz.Through the design of a series of static experiments and dynamic impact experiments,the method of determining the parameters of HJC model for rock material is obtained.That is,the basic mechanical parameters are obtained through the experiment of rock mechanics;The method for determining the pressure parameters in the equation of state can be determined by the Hugoniot impact test data;The method for determining the limit surface parameters and strain rate parameters can be determined by Hopkinson pressure bar(SHPB)experiment;The method for determining the damage parameters is determined by the cyclic compression test on the universal testing machine.Orthogonal numerical simulation method,The plastic strain energy density distribution is used as the evaluation index,The influence of the shock location,wave frequency,disturbance intensity and the depth of the tunnel on the stability of surrounding rock is studied.ANSYS/LS-DYNA numerical simulation software is used to analyze the deformation and failure characteristics of roadway surrounding rock under the static expansion D-P strength criterion and dynamic HJC strength criterion,The results show that when the disturbance intensity is a=2.0m/s~2,the frequency is f=40Hz,the depth is H=1000m,the impact position is=180 degrees,the cross section of the tunnel is U-shaped,The plastic strain energy density is the biggest,and the surrounding rock of the tunnel is prone to be impacted.Based on the existing energy density criterion,The criterion of energy gradient for rock burst energy is proposed,It is determined that the degree of energy accumulation of the surrounding rock can be measured by the change of the energy criterion,and the tendency index of the rock burst can be quantified.