Research on the bearing characteristics and parameter optimization design of variable-section anchor rods
Under the influence of load transfer mechanisms in the surrounding rock-resin anchorage structure, conventional rock bolts exhibit limited utilization of steel tensile capacity due to insufficient axial force at their tail sections. To address the material waste caused by mismatch between anchor rod...
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| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Elsevier
2025-09-01
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| Series: | Results in Engineering |
| Subjects: | |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S2590123025020596 |
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| Summary: | Under the influence of load transfer mechanisms in the surrounding rock-resin anchorage structure, conventional rock bolts exhibit limited utilization of steel tensile capacity due to insufficient axial force at their tail sections. To address the material waste caused by mismatch between anchor rods axial force and tensile capacity, this study proposes a variable cross-section bolt with a hollow tail section. The rational design enables the hollow segment to simultaneously achieve steel conservation and enhanced structural plasticity. By establishing appropriate mechanical models, calculation formulas for bolt axial force and anchorage agent-surrounding rock interface shear stress during elastic stage were derived. Through integrated theoretical analysis and numerical simulation, the influence of hollow segment dimensions on internal force distribution patterns, failure modes, and elastic bearing capacity of the novel bolt’s anchorage section was systematically investigated. The results show that the appearance of hollow section leads to the increase of anchoring agent and surrounding rock interfacial shear stress and the decrease of elastic bearing capacity, and the variation range increases with the increase of hollow section size; When the dimension parameter of the hollow section reaches the critical value, the failure mode of the bolt will change from the slippage of the interface between anchoring agent and surrounding rock to the fracture of the rod at the position of variable section. In the optimization design of the hollow section size, based on the safety consideration, the interface slipping and debonding is determined as the primary failure mode of the new bolt. At the same time, for economic consideration, the optimum hollow section size parameter with the best steel saving effect is selected under the condition of the same reduction of elastic bearing capacity, and the design process of the optimal hollow section size parameter is proposed. This research provides theoretical guidance for improving bolt utilization efficiency, reducing support costs, and optimizing resource allocation in coal roadway engineering. |
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| ISSN: | 2590-1230 |