Study on the failure mechanism of full-length anchorage de-bonding based on anchor agent ring crack propagation
LIANG Dongxu1，ZHANG Nong1，2，3，RONG Haoyu4
(1. School of Civil Engineering，Xuzhou University of Technology，Xuzhou，Jiangsu 221116，China；2. School of Mines，China University of Mining and Technology，Xuzhou，Jiangsu 221116，China；3. State Key Laboratory of Coal Resources and Safe Mining，China University of Mining and Technology，Xuzhou，Jiangsu 221116，China；4. College of Civil and Transportation Engineering，Hohai University，Nanjing，Jiangsu 210098，China)
Abstract：To investigate the de-bonding failure mechanism of the full-length anchorage system and achieve the purpose of constructing high-quality anchor solids. A mechanical model of the bolt-anchor interface was established. The three stages of bolt pulling and sliding lead to the expansion of the anchor ring crack，and the changes of circumferential pressure at the bolt-anchor and anchor-rock interfaces with bolt sliding were analyzed. The locations of the maximum axial force and shear stress were deduced，and the de-bonding failure mechanism of the bolt-anchor interface was revealed. The criteria for de-bonding failure at the bolt-anchor and anchor-rock interfaces were proposed and verified by engineering examples and experiments. The results show that the de-bonding failure of the bolt-anchor interface is in the order of adhesion，mechanical interlocking and friction when the surrounding rock is deformed. The circumferential pressure of the surrounding rock directly affects the peripheral induced circumferential pressure for complete cracking of the anchor ring's radial cracks，and the tensile strength of the anchor determines the interface at which anchor de-bonding occurs. The bolt-anchor interface is de-bonded when the tensile strength of the surrounding rock is greater than the tensile strength of the anchor ring. The anchor ring cracks at the maximum axial tension of the bolt and de-bonds to opposite sides. When the tensile strength of the surrounding rock is less than the tensile strength of the anchor ring，the anchor-rock interface is de-bonded，or the surrounding rock is dislodged. The de-bonding of the anchor-rock interface starts from the bolt loading end and moves to the end of the bolt. How the pullout-resistant anchorage force acts is related to the intact form of the anchor ring，i.e.，bonding and mechanical interlocking when intact，partial bonding and mechanical interlocking after crack initiation，and frictional action after complete fragmentation. The de-bonding of the bolt-anchor interface of the full-length anchorage system fails with the neutral point shift in a cyclic diffusion de-bonding pattern.
梁东旭1，张 农1，2，3，荣浩宇4. 基于锚固剂环裂纹扩展的全长锚固脱黏失效机制研究[J]. 岩石力学与工程学报, 2023, 42(4): 948-963.
LIANG Dongxu1，ZHANG Nong1，2，3，RONG Haoyu4. Study on the failure mechanism of full-length anchorage de-bonding based on anchor agent ring crack propagation. , 2023, 42(4): 948-963.
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2023, Vol. 42 
