Studying On The Characteristics Of Persistent Homology Of Failure Of Underground Rock Mass Under Multi-point Strong Dynamic Load

In this paper,the dynamic response of underground rock mass under multi-point strong dynamic load is studied.Using the discrete element and the persistent homology method,the correlation between the topological characteristics and the failure of underground rock mass under multi-point strong dynamic load is analyzed.Combined with engineering practice,the geometric model of tunnel surrounding rock is constructed based on discrete element method.The dynamic response of tunnel surrounding rock under multi-point strong dynamic load is studied.The failure characteristics and laws of tunnel surrounding rock under multi-point strong dynamic load are analyzed by using maximum displacement diagram and plastic failure diagram.The 0-dimensional Betti number bar code of two groups of tension failure points is analyzed and compared,and the overall length of the bar code can be used as the judgment basis of the overall displacement mutation,compared with the 1-dimensional Betti number barcode,it is found that the effective explosion load can reduce the number of holes formed by tension failure.The failure conditions of tunnel surrounding rock under different joint dip angles under the action of explosion load and without explosion load are discussed respectively.It is found that the failure of tunnel surrounding rock is mainly caused by the sliding and opening of joints,and the impact of explosion wave on the damage of tunnel surrounding rock is weak;when the joint angle is close to the friction angle of rock mass,the damage of rock tunnel surrounding rock is the most serious.Based on the analysis of the bar code diagram,the damage condition of the tunnel surrounding rock is obtained.Through the0-dimensional Betti number bar code diagram,the distribution state of tension failure point of the tunnel surrounding rock can be obtained,and its flatness can be used to judge the failure state of the tunnel surrounding rock.When using these features of the 0-dimensional Betti number bar code to obtain the 35° dip joint,the tunnel surrounding rock has the greatest damage.Combining the overall length of the 0-dimensional Betti number bar code diagram,it can be judged that the maximum displacement is produced when the 35° dip joint is joined.The 1-dimensional Betti number bar code graph can also show the overall characteristics of the tension failure point,but because the coordinate point required by the 1-dimensional Betti number bar code graph is a bit harsh,this is reflected in the connected radius,so the combination of the 0-dimensional Betti number bar code map and the 1-dimensional Betti number bar code map can more accurately and clearly reflect the damage of the tunnel surrounding rock.