循环载荷作用下高应力岩石疲劳损伤破坏数值模拟与试验研究  

Experimental and numerical study of fatigue damage of highly stressed rocks under cyclic loading

作　　者：赵博[1] 徐涛[1] 杨圣奇[2] 付腾飞 ZHAO Bo;XU Tao;YANG Shengqi;FU Tengfei(Center for Rock Instability and Seismicity Research,Northeastern University,Shenyang 110819,China;State Key Laboratory for Geomechanics and Deep Underground Engineering,China University of Mining and Technology,Xuzhou 221116,China)

机构地区：[1]东北大学岩石破裂与失稳研究所,辽宁沈阳110819 [2]中国矿业大学深部岩土力学与地下工程国家重点实验室,江苏徐州221116

出　　处：《中南大学学报（自然科学版）》2021年第8期2725-2735,共11页Journal of Central South University:Science and Technology

基　　金：国家自然科学基金资助项目(51974062,41672301)。

摘　　要：开展不同上下限应力比条件下砂岩的损伤破裂过程试验,然后基于颗粒流数值模拟方法,引入应力腐蚀模型反映应力作用下岩石的疲劳损伤过程。根据室内试验标定得到模型的瞬时和时效细观参数,通过对比验证时效变形损伤破裂模型的合理性。在此基础上开展不同上下限应力比条件下岩石疲劳破坏的数值模拟及室内试验研究。研究结果表明:疲劳载荷作用下,岩石的损伤破坏曲线中的滞回环呈现出"疏-密-疏"的演化特点,且裂隙发育曲线在加载初期呈上凸型减速上升,随后稳定发展,最后呈下凸型加速上升直至破坏,整体呈阶梯状增长。疲劳荷载的下限应力水平一定时,上限应力水平越大,滞回环面积和间距越大,循环次数越少,模型疲劳寿命越短;当上限应力水平一定时,下限应力水平越大,应力幅值越小,滞回环面积和间距越小,循环次数越多,但是损伤破坏时间相近,应力上限是影响岩石疲劳寿命的重要因素之一。The damage and fracture tests of sandstone at different upper and lower stress ratios were performed,and a stress corrosion model based on the particle flow code method was introduced to reflect the fatigue damage process of the rock under cyclic stress. The instantaneous and time-dependent parameters at a mesoscale in the model were calibrated against laboratory tests, and the established time-dependent deformation damage and rupture model comparatively justified. Furthermore, the experimental and numerical tests on rock at various upper and lower stress ratios were performed. The results show that the hysteresis loop in the damage failure curve of the model presents the characteristics of ’sparse-dense-sparse’, and the curve presents a convex deceleration rise at the beginning of loading and then develops steadily, and finally, it accelerates up to failure in a step-wise downward convex trend. When the lower limit stress level of the fatigue load is fixed, the higher the upper limit stress level,the larger the area and spacing of the hysteresis loops, the fewer the cycles, and the shorter the fatigue life of the model. When the upper limit stress level is fixed, the higher the lower limit stress level, the smaller the stress magnitude, the smaller the area and spacing of the hysteresis loops, the fewer the cycles, but the fatigue life of the model is almost identical, which indicates that the upper limit stress is one of the important factors affecting the fatigue life of rock.

关 键 词：疲劳荷载 应力腐蚀模型 上下限应力比 颗粒流PFC3D 裂纹扩展 

分 类 号：TU458[建筑科学—岩土工程]