基于RHT模型双孔同时爆破均质岩体损伤的数值模拟

为探究双孔爆破时炮孔间距和额外自由面对爆破过程中爆破损伤的影响，基于RHT（Riedel-Hiermaier-Thoma）损伤本构建立了多组三维数值模型，利用模型损伤云图研究不同爆破条件下的岩石爆破过程，通过自定义变量—有效损伤率的变化探究炮孔周围岩石损伤的时空演化过程。结果表明：随着炮孔间距的增加，岩石有效损伤率逐渐递减，相同截面处的有效损伤率在炮孔间距最小的方案中最大，相邻炮孔间的爆破能量叠加作用随炮孔间距的增大而减弱，合适的炮孔间距可以获得更加理想的爆破效果；岩石有效损伤率随着自由面到炮孔中心处距离的增大而逐渐减小，爆破能量倾向于向自由面方向传播，额外自由面对爆破能量分布的影响随自由面与炮孔间距的增大而减弱。数值模拟结果对研究双孔爆破能量的传递法则具有一定的借鉴意义。

Numerical Simulation of Homogeneous Rock Mass Damage Caused by Two-hole Simultaneous Blasting Based on RHT Model

Due to the complex nature of rock mass and the different transfer modes of explosive energy，it is difficult to control the blasting process and blasting effect.After blasting，the damage of rock mass around blast holes is related to the bearing capacity and stability of the project.In order to explore the influence of blast hole spacing and additional free surface on the blasting process and effect during double-hole blasting，a double-hole blasting model was established based on RHT （Riedel Hiermaier Thoma） damage constitutive model by using LS-DYNA finite element software to simulate rock blasting damage under different working conditions.The experiment of previous scholars was repeated by numerical simulation，and the test results were compared with the numerical simulation results in this paper to verify the feasibility of the numerical simulation method and the rationality of the selection of material parameters.Through the comparative analysis between numerical simulation results and blasting experimental results，it is determined that the rock blasting damage threshold applicable to this paper is 0.5 based on the blasting mechanism，and the rock damage value greater than 0.5，which is called the effective damage of rock.The effective damage rate of rock is defined as the proportion of the effective damage range of rock in the plane damage cloud map to the total plane area.The change of effective damage rate of rock is used to intuitively show the temporal and spatial evolution law of rock damage in the blasting process.The rock damage nephograms at different times were intercepted to observe the damage in different directions of the rock after blasting.The damage nephograms were processed by LS-PrePost to obtain the distribution range of effective damage on the plane.Then，the MATLAB program was used to calculate the effective damage rate，and the numerical calculation and analysis were carried out.The results show that the effective damage rate of rock decreases with the increase of blast hole spacing，and the effective damage rate at the same section is the largest in the scheme with the smallest blast hole spacing.The superposition effect of blasting energy between adjacent blastholes decreases with the increase of blast hole spacing，and a more ideal blasting effect can be obtained with an appropriate blast hole spacing.The effective damage rate of rock decreases gradually with the increase of the distance between the free surface and the center of the blast hole，and the blasting energy tends to propagate to the free surface.The influence of additional free surface on the distribution of blasting energy decreases with the increase of the distance between the free surface and the blast hole.