State Key Laboratory of Coal Mine Safety Technology, China Coal Technology and Engineering Group, Shenyang Research Institute, Shenfu Demonstration Zone, Shenyang, 113122, China.
College of Mechanics and Engineering, Liaoning Technical University, Fuxim, 123000, China.
Sci Rep. 2023 May 9;13(1):7497. doi: 10.1038/s41598-023-34246-0.
To investigate the influence of the weak layer dip angle on the creep rupture of the composite rock mass, this paper conducts a graded loading creep experiment on the composite rock mass with different dip angles using the acoustic emission method to examine the fracture evolution process. With increasing load grade, the cumulative total ring count of the rock mass shows a "U"-shaped trend, and the acoustic emission spatial positioning results show that acoustic emission events in the rock mass fracture process are primarily concentrated in the vicinity of the weak layer, while events in other areas are few and dispersed. For rock masses with weak layer dip angles of 0° and 15°, cracks occur in both soft and hard rocks, where shear cracks are dominant in soft rocks, tensile cracks are dominant in hard rocks, and finally, the rock mass mainly exhibits tensile splitting failure. For rock masses with weak layer dip angles of 30° and 45°, most of the cracks exist in the interior of the soft rock, which is dominated by shear cracks. With increasing graded loads, the shear cracks continue to develop along the direction of the weak layer, the upper rock mass keeps slipping and dislocating, and the final failure mode is mainly shear-slip failure. The damage evolution varies with the inclination angle of the weak layer, which can be divided into three stages: initial damage accumulation, damage acceleration, and damage destruction. This demonstrates the ability to predict, prevent, and control the occurrence of creep disasters in rock masses with weak layers.
为了研究软弱层面倾角对复合岩体蠕变破裂的影响，本文采用声发射方法对不同倾角的复合岩体进行分级加载蠕变试验，研究了断裂演化过程。随着载荷等级的增加，岩体的累计总环数呈现出“U”形趋势，声发射空间定位结果表明，岩体断裂过程中的声发射事件主要集中在软弱层面附近，而其他区域的事件较少且分散。对于软弱层面倾角为 0°和 15°的岩体，软、硬岩中均发生裂缝，软岩中以剪切裂缝为主，硬岩中以拉伸裂缝为主，最终岩体主要表现为拉伸劈裂破坏。对于软弱层面倾角为 30°和 45°的岩体，大部分裂缝存在于软岩内部，以剪切裂缝为主。随着分级载荷的增加，剪切裂缝沿软弱层方向继续发展，上部岩体不断滑动和错动，最终破坏模式主要为剪切滑移破坏。损伤演化随软弱层倾角的变化而变化，可分为三个阶段：初始损伤积累、损伤加速和损伤破坏。这证明了能够预测、预防和控制软弱层岩体蠕变灾害的发生。
