Calibration Of HJC Constitutive Parameters Of Huashan Granite And Its Blasting Damage Numerical Simulation

The dyna mic blast ing damage assessment of rock is an important part of engineer ing ant i-knock research,the current theoretical research leve l has to be improved in describ ing vario us aspects of blasting,the cost required for the experime nt is high,the imp le mentat io n period is long,and it is diffic ult to measure the re leva nt parameters complete ly and accurately.Wit h t he increase of computat iona l le ve l,numer ica l s imulat ion tec hno logy can not only per fect ly reproduce the various processes of blasting dama ge,but also effective ly describe the dyna mic response of rock under b last loading,t hus is used by a large number of scie nt ific researchers.Studies have shown t hat choosing suitable const it ut ive model a nd mode l parameters,us ing reasonab le mes hing met hod,and combining an excelle nt numer ical a lgor it hm are the guarantees for obtaining accurate and effic ient s imulat ion res ults.In order to improve the accuracy of numer ica l simulat ion,focus ing on the scient ific issues of blast ing damage to Huashan granite,following tasks are carried out:First ly,a group of Holmq uist-Johnson-Cook(referred to as HJC)constitut ive parameters of rock were determined by basic experiment,theoretica l calc ulat ion and empir ica l va lue,the finite ele me nt software of ANSYS/LS-DYNA was used to simulate t he blast ing dama ge of rock.Based on this,the different fa ilure types of ele ments and t he sensit ivity o f the HJC constit ut ive parameters were analyzed.It turned out that the maximum tens ile stress failure type is suitable for blast ing da mage s imulat ion,and the HJC constit ut ive parameters have differe nt sens it ivit ies to the results of the calc ulat ion results,among whic h??G?B?N and f_c exert great influence on the peak velocit y and peak displacement,so more attention should be paid when these parameters are determined.The n,the derivat ion process and properties of t he programmed grad ient mes h partit ion funct io n was introduced in detail,and t he influence of d ifferent mesh precisio n on the calc ulat ion results was discussed based on the unifor m mesh and the gradient mesh.It was found that the calc ulat ion results were affected not only by t he mesh s ize of t he medium itse lf,but a lso by t he ratio o f adjacent mesh s ize,and the size of adjacent mesh should not be too large.In the case of the same ca lculat io n precis io n,the comp utat iona l storage space required for the gradient mesh is less than that of the uniform mesh.Fina lly,the coup ling a lgor it hm of t he s mooth part icle(SPH)and the finite ele ment(FEM)was introduced,the detailed modeling process was give n with the examp le of blast ing s imulat ion,and the impact of different part icle generat ion and different partic le range on the blast ing s imulat io n results were analyzed.The results show that t he SPH particles generated by the geometr ic shape are evenly distr ib uted,and the simulat ion of rock blast ing effect is good when coup ling wit h t he finite e le ment.Moreover,when t he partic le range is too sma ll,the coupling between SPH partic les and finite ele ments will be affected.And while t he partic le range is too large,the co mputat ion t ime a nd storage space will increase.Therefore,it is suggested that the reasonable particle ra nge is about 12~16 times of the explosive radius.