Experimental and numerical studies on progressive debonding of grouted rock bolts
Experimental and numerical studies on progressive debonding of grouted rock bolts
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DOI：
10.1016/j.ijmst.2021.10.002
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发表时间：
2022-01-01
影响因子：
11.8
通讯作者：
Zhao, Huayun
中科院分区：
文献类型：
--
作者：
Shi, Hao;Song, Lei;Zhao, Huayun
了解锚杆渐进脱粘机理对于井下安全具有重要意义。本文对拉拔试验进行了室内实验和数值模拟。采用水泥砂浆材料制备实验拉拔试验试件，建立了螺栓的拉拔强度与水泥砂浆材料试件单轴抗压强度（UCS）之间的关系。使用声发射（AE）技术识别拉拔过程中产生的裂纹位置。使用具有校准参数的 2D 粒子流代码 (PFC2D) 重现拉拔测试。实验结果表明，对于所有强度的水泥基灌浆料，试验过程中峰值荷载下水泥砂浆材料的轴向位移约为5 mm。相反，螺栓的峰值载荷随着限制介质的 UCS 的增加而增加。在峰值载荷下，裂纹扩展至不到锚固长度的一半，表明裂纹扩展和轴向螺栓载荷传递之间存在滞后。模拟结果表明，锚杆与岩石之间的膨胀引起裂纹，并使力场沿锚固方向扩展；并且，它被认为是导致锚杆拔出失效的主要因素。 (C) 2021 由 Elsevier B.V. 代表中国矿业大学出版。
Understanding the mechanism of progressive debonding of bolts is of great significance for underground safety. In this paper, both laboratory experiment and numerical simulation of the pull-out tests were performed. The experimental pull-out test specimens were prepared using cement mortar material, and a relationship between the pull-out strength of the bolt and the uniaxial compressive strength (UCS) of cement mortar material specimen was established. The locations of crack developed in the pull-out process were identified using the acoustic emission (AE) technique. The pull-out test was reproduced using 2D Particle Flow Code (PFC2D) with calibrated parameters. The experimental results show that the axial displacement of the cement mortar material at the peak load during the test was approximately 5 mm for cement-based grout of all strength. In contrast, the peak load of the bolt increased with the UCS of the confining medium. Under peak load, cracks propagated to less than one half of the anchorage length, indicating a lag between crack propagation and axial bolt load transmission. The simulation results show that the dilatation between the bolt and the rock induced cracks and extended the force field along the anchorage direction; and, it was identified as the major contributing factor for the pull-out failure of rock bolt. (C) 2021 Published by Elsevier B.V. on behalf of China University of Mining & Technology.