岩质边坡岩体内普遍存在不连续裂隙，边坡开挖卸荷诱发裂隙扩展贯通是导致滑坡失稳的主要因素。为探究卸荷条件下边坡岩体内裂隙扩展机制和相互作用规律，基于经典Kachanov法和叠加原理，推导了卸荷条件下一对不等长共线裂隙尖端应力强度因子表达式。定义了应力强度因子比F(双裂隙存在时与单裂隙存在时裂隙尖端应力强度因子比)，通过F值的大小分析了裂隙倾角、间距和长度对裂隙间相互作用的影响规律。进行了类岩石材料双轴卸荷实验，类岩石材料由425号普通硅酸盐水泥、标准砂、水按质量比1∶2.35∶0.5配制而成，实验在MS-500型三轴冲击岩爆试验系统上进行。结果表明:① 裂隙倾角对裂隙间相互作用无影响;② 裂隙间距开始大于任一裂隙长度时，该裂隙几乎不影响另一裂隙扩展;③ 裂隙长度大于裂隙间距时，该裂隙开始影响另一裂隙扩展。裂隙长度小于裂隙间距时，该裂隙几乎不影响另一裂隙扩展;④ 试件轴向起裂和峰值荷载随着裂隙间距的增大而增大。理论计算和实验所得裂隙起裂角及起裂位置基本一致，验证了理论计算结果的可行性与合理性。本次研究没有考虑裂隙充填对裂隙间相互作用规律的影响，且仅限于共线双裂隙间相互作用的探讨，后续研究将在考虑裂隙充填情况下，继续探讨共线三裂隙以及多裂隙间相互作用规律。

It is common to have discontinuous cracks in the slope rock mass,whose extension and penetration induced by slope excavation and unloading are the main factors leading to landslide instability.To study the failure mechanism and interaction between cracks in a slope under unloading condition,based on the classical Kachanov method and superposition principle,the expression of stress intensity factor at the tip of a pair of unequal collinear cracks under the condition of unloading was derived.The stress intensity factor ratio F(the ratio of stress intensity factor at the tip of a crack in the presence of double cracks to that at the tip of a single crack) was defined,and the effects of crack inclination angle,spacing and length on the interaction between cracks were analyzed by the value of F.The biaxial unloading experiment of rock like materials was carried out,and the rocklike material was made up of 425 ordinary portland cement,standard sand and water according to the mass ratio of 1∶2.35∶0.5,and the experiment was carried out on MS500 triaxial impact rockburst test system.The results show that:① the dip angle of the crack has no effect on the interaction between the cracks;② when the crack spacing begins to be larger than the length of any crack,this crack has little effect on the propagation of the another crack;③ when the crack length is larger than the crack spacing,this crack begins to affect the propagation of another crack.When the crack length is less than the crack spacing,this crack has little effect on the propagation of another crack;and ④ axial initiation and peak load of specimens increase with the increase of crack spacing.The initiation angle and the initiation position are basically in agreement with theory and experiment,thus the feasibility and rationality of the theoretical calculation results are further verified.In this study,the effect of crack filling on the interaction between cracks is not considered,and it is limited to the interaction between two collinear cracks.The subsequent study will continue to explore the law of interaction between collinear three cracks and multiple cracks in the case of crack filling.

1 卸荷条件下不等长共线裂隙应力强度因子求解

    1.1 卸荷条件下不等长共线双裂隙断裂力学模型分析

    1.2 单轴拉伸作用下裂隙尖端应力强度因子KC的求解

    1.3 单轴压缩作用下裂隙尖端应力强度因子KB的求解

    1.4 卸荷条件下双裂隙尖端应力强度因子KA的求解

    1.5 卸荷条件下单裂隙尖端应力强度因子KD的求解

2 卸荷作用下不等长共线裂隙之间相互作用规律分析

    2.1 裂隙倾角的影响

    2.2 裂隙间距的影响

    2.3 大裂隙长度的影响

    2.4 小裂隙长度的影响

3 含不等长共线裂隙类岩石材料卸荷试验

    3.1 试验条件

    3.2 试验试样制备

    3.3 试验方案

    3.4 裂隙扩展过程分析

    3.5 试样裂隙起裂及极限荷载分析

4 结论