相较于贯通节理，岩桥的存在使非贯通节理岩体受力破坏过程更加复杂，为探明其对破岩影响，通过采用PFC2D建立单向非贯通节理岩体滚刀破岩离散元模型，探究以不同岩桥长度和倾角组合下为变量，研究对的岩体破碎模式、法向力、裂纹数量及比能耗等参数的影响，揭示了非贯通节理岩体滚刀破岩特性。研究发现:岩体以张拉破坏为主,节理对裂纹扩展的“导向作用”明显,裂纹扩展方向总是趋向于和其距离最近的节理；竖向应力水平随节理倾角增加呈现先增大后减小的趋势,在45°倾角下达到最大值,应力区形状受到节理位置影响,两者具有一致性；完整岩体法向力均值和峰值均大于节理岩体,节理对于破岩过程具有明显的促进作用；0°、60°、90°节理倾角下的比能耗值明显低于其他节理组合,60°倾角下呈减小趋势,在岩桥长度为25mm时取得最小值；0°、90°倾角下呈先减小后增大趋势,在岩桥长度为15mm时取得最小值。

Compared with the penetrating joint, the existence of rock bridge makes the failure process of non-penetrating jointed rock mass more complicated. In order to explore its influence on rock breaking, the discrete element model of rock breaking by disc cutter in unidirectional non-penetrating jointed rock mass is established by using PFC2D. The influence of rock bridge length and dip angle on rock breaking mode, normal force, crack number and specific energy consumption is studied, and the rock breaking characteristics of disc cutter in non-penetrating jointed rock mass are revealed. The results show that the rock mass is dominated by tensile failure, and the joint has obvious "guiding effect" on crack growth, and the crack growth direction always tends to the nearest joint. The vertical stress level increases first and then decreases with the increase of joint dip Angle, and reaches the maximum value at 45° dip Angle. The shape of the stress zone is affected by the joint position, and the two are consistent. The mean value and peak value of normal force of intact rock mass are greater than jointed rock mass, and jointed rock has obvious promoting effect on rock breaking process. The specific energy consumption at 0°, 60° and 90° joint dip Angle is significantly lower than that of other joint combinations. The energy consumption decreases at 60° joint dip Angle, and the minimum value is obtained when the length of rock bridge is 25mm, at 0° and 90°, it decreases first and then increases, and the minimum value is obtained when the length of the rock bridge is 15mm.

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福建省科技计划引导性项目(2020H0014)