为了研究大型硐室或边坡中不同倾角岩体结构面在动力扰动下的变形特征和破坏机理，采用微控电液伺服疲劳试验机对不同倾角结构面岩石进行不同振幅的周期性动力扰动力学试验，实验结果表明:动力扰动下结构面岩石试件发生破坏时产生大量的沿着轴向发展的竖向裂纹，随后结构面岩石试件碎裂成相对较薄的片状或条状碎屑，在宏观上表现出沿着结构面倾向膨胀;每次加、卸载的应力应变曲线都会形成一条封闭的滞后环曲线，且该曲线总体呈现出疏-密-疏3个阶段的特征;在结构面岩体倾角一定时，滞后环曲线的面积及岩体的变形模量随着扰动应力幅值的增大而增大，表明扰动振幅增加使得扰动岩石在每个循环周期中内部积聚更多可消耗的能量，用于矿物颗粒之间的黏滑消耗以及原有微裂纹的增生和新裂纹的产生，导致岩石达到破坏所需的累积不可逆变形总量会降低，劣化试件的抗载性能;当扰动应力幅值一定时，滞后环曲线的变化幅度随着结构面岩体倾角的逐渐增大而增大，岩体的变形模量随之减小，岩石的阻尼比呈现先减小，然后稳定，再增大的趋势，反映了岩石中裂隙从初始变形(空隙压密)到等速变形(微破裂稳定发展)到加速变形(裂隙贯通)后整体破坏的过程;结构面岩石试件发生破坏的扰动应力幅值存在一个可用静载荷和结构面倾角进行确定的扰动阈值，当扰动应力幅值＜扰动阈值时，随着循环加卸载周期的增大，塑性应变值趋于稳定值，结构面岩石未发生破坏，岩石塑性应变积累值与扰动循环加载次数符合负指数函数，反之，当扰动应力幅值＞扰动阈值时，岩石塑性应变积累值与扰动循环加载次数的关系符合朗之万函数逆函数，对这2种函数中待定参数值变化对损伤曲线簇的影响规律分析，确定了该函数中待定参数的物理意义，并通过不同振幅循环加卸载条件下不同倾角结构面岩石内部能量变化过程分析，揭示了结构面岩石在循环荷载作用下的能量破坏机制。

In order to study the deformation characteristics and failure mechanism of discontinuous rock mass with different inclination angles in large cavern or slope under dynamic disturbance,some periodic dynamic perturbation mechanics tests of rocks with different dip angles were carried out using electrohydraulic servo universal testing machines.The experimental results show that a large number of vertical cracks along the specimens axial direction are generated and subsequently the rock structural specimens are broken into relatively thin pieces or strips of debris when the structural surface specimens are damaged under the dynamic disturbance.The loading and unloading curves of the rock mass discontinuity do not coincide,and a closed hysteresis loop curve is formed.The overall stressstrain hysteresis loop curve of the rock discontinuity under dynamic disturbance has three stages:sparse,dense and sparse.When the dip angle of rock discontinuity is constant,the area of hysteresis loop curve and the deformation modulus of rock mass increase with the increase of disturbance stress,which indicates that the increase of disturbance stress makes the disturbed rock accumulate more consumable energy in each cycle that is used for the consumption of stick slip between mineral particles,the growth of original micro cracks and the generation of new cracks.The total amount of cumulative irreversible deformation that leads to rock failure is reduced,which deteriorates the load resistance of the specimens.When the disturbance stress is fixed,the large variation range of the hysteresis loop curve increases with the increase of the dip angle of the structural plane and the deformation modulus of the rock mass decreases.The damping ratio of rocks with different inclinations decreases first,then stabilizes,and then increases,which reflects the process of fracture failure in rock from initial deformation (pore compaction) to constant deformation (stable development of micro fracture) to accelerated deformation (crack connection).There is a disturbance threshold which can be determined by static load and inclination of the structural plane.When the disturbance stress is lower than the disturbance threshold,with the increase of cyclic loading and unloading period,the plastic strain value tends to be stable,and the rock structural surface is not damaged.The number of loading and unloading cycles and the variation of the cumulative plastic strain correspond to a negative exponential function.When the disturbance stress is higher than the disturbance threshold,these values correspond to an inverse Langevin function.The physical significance of the undetermined parameters in the function is determined by analyzing the influence of undetermined parameters on the damage curve cluster,and the energy failure mechanism of rock under cyclic loading is revealed through the analysis of internal energy change process of rock discontinuity with different inclination angles under different amplitude dynamic disturbance.These results have practical significance and academic value for the engineering design,disaster prevention and control of deep rock structural plane engineering.

1 试验设备及方案

    1.1 实验设备

    1.2 试件制备

    1.3 循环动力扰动实验方法及方案

2 循环动力扰动下单轴实验结果分析

    2.1 动力扰动作用下应力-应变曲线变化规律

    2.2 动力扰动作用下结构面岩石塑性应变演化规律

    2.3 扰动下结构面岩石强度弱化能量原理

3 结论