In order to explore the rationality of the parameter selection for the numerical model of limestone under the action of impact load,a numerical analysis method for the impact failure of limestone was constructed based on the Holmquist-Johnson-Cook(HJC) constitutive model.At the same time,static tests were carried out on the limestone drilled in Tongzi tunnel,and the basic physical and mechanical parameters were obtained.First,the rock sample limit surface parameters,pressure parameters and rate effect parameters were obtained through triaxial confining pressure experiments,Hopkinson pressure bar and other experiments.Then,LS-DYNA numerical simulation and SHPB tests were carried out,and the results were compared.Finally,the sensitivity analysis of 21 parameters of the limestone HJC constitutive model was carried out with the dynamic peak stress as the objective function.The results show that the numerical calculation is in good agreement with the stress-strain curve and the failure form obtained from the SHPB laboratory tests,indicating the rationality of the parameters of the limestone HJC constitutive model in this paper.The strength of the limestone is sensitive to the parameters fc,A,B,and N,and either the maximum change rate of its intensity increase or decrease exceeds 10%.