Analysis Of Rockburst Caused By Dynamic Disturbance Of Deep Tunnel And Its Program Implementation

In the process of excavation,deep tunnels are subject to different types of disturbances,such as earthquakes,mechanical vibrations,blasting,etc.These disturbances can destroy the stability of the surrounding rock and lead to the occurrence of rock bursts.Rock burst is a common destruction phenomenon in deep underground engineering during excavation.Because of the existence of the ground stress,when the surrounding rock is subjected to dynamic disturbance,it will cause dynamic catapult rupture and serious disaster.Therefore,the prediction of rock burst,the analysis of on-site ground stress and the prevention of rock burst in the construction of deep-buried tunnels have become a difficult problem to solve.Based on rock burst criterion and the relevant theories of yield criterion,numerical simulation software is used to analyze the rock burst prediction of deep tunnels under different forms of dynamic disturbances and the secondary development of related yield criteria.The major contents were following:?1?Based on the theory of dynamic disturbances,the ABAQUS finite element software was used to establish a tunnel numerical model,the effects of different forms of dynamic disturbances,different lateral pressure coefficients and the thickness of the lining on the stability of surrounding rock were analyzed.We also discussed the law of plastic damage in surrounding rock.We concluded that when the same period and the same amplitude are obtained,the plastic failure of the surrounding rock under trapezoidal form is the most serious.?2?According to the Tao Zhenyu rock burst criterion,the impact of different forms of dynamic disturbance on rock burst induction was compared.The degree and laws of rockburst response under dynamic disturbance were also analyzed.The critical length of rock burst induced by different degrees of rockburst was revealed.Different degrees of critical period induced by rock burst,and the maximum principal stress generated is revealed.?3?A rock elastic-plastic UMAT subroutine on the basis of the double T² yield criterion is given.After the verification with Mises yield criterion of the ABAQUS,the subroutine parameters ? are discussed.?4?On the basis of the double T² yield,the UMAT subroutine of the generalized doublet² strength theory was developed.By discuss the UMAT subroutine numerical simulation results and theoretical solutions prove that the subroutine is true.Futhermore,the impact of parametersK₀ on the subroutine is discussed.?5?According to the double T² yield criteria subroutine,rock burst predictions were made for the Shawan tunnel which the phyllite was as the main tunnel surrounding rock.Combined with the Erlangshan rockburst criterion and the Taozhenyu rockburst criterion,we can determine the level of cave burst induced by cave load.The results show that the double T² yield criterion subroutine is feasible.This research has certain guiding significance for the construction of future tunnel projects.It can select the corresponding yield adapttion for different projects by change the parameters ?to enhance the accuracy of simulation.