Failure mechanism of fully grouted rock bolts subjected to pullout test: Insights from coupled FDM-DEM simulation

IF 3.4 2区工程技术 Q2 ENGINEERING, GEOLOGICAL

International Journal for Numerical and Analytical Methods in Geomechanics Pub Date : 2024-08-26 DOI:10.1002/nag.3824

Hongyan Zhao, Kang Duan, Yang Zheng, Qiangyong Zhang, Longyun Zhang, Rihua Jiang, Jinyuan Zhang

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引用次数: 0

Abstract

Fully grouted rock bolts are widely used in mining, tunneling, and pit support, and thus the study of their anchorage performance is beneficial for optimizing the anchorage system design. In this study, an FDM-DEM coupled numerical model is established to simulate the whole process of rock bolt pullout test and to investigate the failure mechanism of fully grouted rock bolts. The accuracy of the model is verified by comparison with existing laboratory test results. Virtual experiments are conducted on different models by eliminating the anchor plate, changing the layered rock strata condition, and adding bolts. The results show that the presence of an anchor plate will reduce tensile stress to restrain the rupture of surrounding rock and thus improve the strengthening effect. Due to the different bond strength and tensile strength of the soft and hard rock mediums, the layer sequence of the rock strata affects the maximum pullout force. The upper-soft and lower-hard composite rock strata (S-HCR) exhibits single-cone damage while the upper-hard and lower-soft composite rock strata (H-SCR) exhibits double-cone damage. The superposition effect of the anchor group on the stresses and displacements is the reason leading to the reduction of the maximum load-bearing capacity of the rock bolts.

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接受拉拔试验的全灌浆岩石螺栓的失效机理：FDM-DEM 耦合模拟的启示

全灌浆岩石螺栓广泛应用于采矿、隧道和基坑支护，因此对其锚固性能的研究有利于优化锚固系统设计。本研究建立了 FDM-DEM 耦合数值模型，模拟岩石螺栓拉拔试验的全过程，研究全灌浆岩石螺栓的破坏机理。通过与现有实验室测试结果的对比，验证了模型的准确性。通过取消锚板、改变分层岩层条件和增加螺栓，对不同模型进行了虚拟试验。结果表明，锚固板的存在会降低拉应力，抑制围岩破裂，从而提高加固效果。由于软硬岩介质的粘结强度和抗拉强度不同，岩层的层序会影响最大拉拔力。上软下硬复合岩层（S-HCR）表现为单锥破坏，而上硬下软复合岩层（H-SCR）则表现为双锥破坏。锚杆组对应力和位移的叠加效应是导致岩石锚杆最大承载能力降低的原因。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

International Journal for Numerical and Analytical Methods in Geomechanics 工程技术-材料科学：综合

CiteScore

6.40

自引率

12.50%

发文量

160

审稿时长

9 months

期刊介绍： The journal welcomes manuscripts that substantially contribute to the understanding of the complex mechanical behaviour of geomaterials (soils, rocks, concrete, ice, snow, and powders), through innovative experimental techniques, and/or through the development of novel numerical or hybrid experimental/numerical modelling concepts in geomechanics. Topics of interest include instabilities and localization, interface and surface phenomena, fracture and failure, multi-physics and other time-dependent phenomena, micromechanics and multi-scale methods, and inverse analysis and stochastic methods. Papers related to energy and environmental issues are particularly welcome. The illustration of the proposed methods and techniques to engineering problems is encouraged. However, manuscripts dealing with applications of existing methods, or proposing incremental improvements to existing methods – in particular marginal extensions of existing analytical solutions or numerical methods – will not be considered for review.