基于UDEC的岩体完整性系数对岩爆烈度影响的离散元分析

Discrete Element Analysis on the Influence of Rock Mass Integrity Coefficient on Rockburst Intensity Based on UDEC

摘要: 针对多数学者在岩爆预测指标选取中并未考虑岩体完整性系数K_V对岩爆烈度预测准确率的作用，为进一步明确岩爆发生时岩体完整性系数K_V对岩爆烈度的影响，本文以江边水电站引水隧洞为工程案例，基于弹性应变能理论，利用UDEC离散元软件建立隧洞开挖数值模型，通过在岩体中设置结构面间距分别为0.5 m、0.75 m、1 m、2 m的两组平行相交结构面，模拟隧洞开挖过程中岩体的力学行为特征，并分析围岩岩爆破坏时的弹性应变能云图、应力云图、位移云图以及弹射岩块速度云图。结果表明，随着结构面间距的增大，即岩体完整性的提高，岩体发生破坏时所需的能量越高，产生的应力、位移、弹射速度也越大，即岩爆烈度越大。

Abstract: Addressing the fact that most scholars have not considered the role of rock mass integrity coefficient (K_V) in improving the accuracy of rockburst intensity prediction in selecting predictive indicators, this study aims to further clarify the influence of rock mass integrity coefficient (K_V) on rockburst intensity during rockburst events. Taking the water diversion tunnel of Jiangbian Hydropower Station as a case study, based on the theory of elastic strain energy, a numerical model of tunnel excavation is established using the UDEC discrete element software. Two sets of parallel intersecting structural planes with spacings of 0.5 m, 1 m, 1.5 m, and 2 m are set within the rock mass to simulate the mechanical behavior of the rock mass during tunnel excavation. Subsequently, the elastic strain energy contours, stress contours, displacement contours, and ejection velocity contours of rock fragments during surrounding rockburst failure are analyzed. The results indicate that with the increase in the spacing between structural planes, which signifies an improvement in rock mass integrity, the energy required for rock failure increases, leading to higher stresses, displacements, and ejection velocities. In other words, the rockburst intensity intensifies.