汤旭东, 张家驰, 聂雯. 全长锚固锚杆锚固单元力学性能实验研究. 力学与实践, 2023, 45(5): 1044-1056. DOI: 10.6052/1000-0879-23-333
引用本文: 汤旭东, 张家驰, 聂雯. 全长锚固锚杆锚固单元力学性能实验研究. 力学与实践, 2023, 45(5): 1044-1056. DOI: 10.6052/1000-0879-23-333
Tang Xudong, Zhang Jiachi, Nie Wen. Experimental study on shearing features of anchorages for fully-grouted rebar. Mechanics in Engineering, 2023, 45(5): 1044-1056. DOI: 10.6052/1000-0879-23-333
Citation: Tang Xudong, Zhang Jiachi, Nie Wen. Experimental study on shearing features of anchorages for fully-grouted rebar. Mechanics in Engineering, 2023, 45(5): 1044-1056. DOI: 10.6052/1000-0879-23-333

全长锚固锚杆锚固单元力学性能实验研究

EXPERIMENTAL STUDY ON SHEARING FEATURES OF ANCHORAGES FOR FULLY-GROUTED REBAR

  • 摘要: 锚固单元的传力特性是影响全长锚固锚杆支护能力的重要因素。由于锚固单元界面构成复杂,本文主要考虑锚杆与粘结材料及其界面的力学特性,开展锚固单元界面剪切力学实验研究。实验结果表明,砂浆强度直接影响界面的峰值强度和剪切刚度;采用相同强度砂浆,界面的峰值强度、剪切刚度和残余剪切强度都与法向应力成正比;在相同法向应力作用下,剪切速率增加引起峰值剪切强度增大,但对残余剪切强度影响较小。依据实验剪切应力–位移曲线将锚固单元与岩石间界面的解耦过程分为“峰前–软化–滑移”三阶段,非连续变形分析方法数值模拟结果表明,加载初期的损伤主要受粘结材料抗拉强度的影响,临近峰值阶段与粘结材料张剪混合破裂相关;软化阶段和滑移阶段主要受粘结材料剪切特性和颗粒形状的影响;引入实验所获得的三线滑移模型曲线到全长锚固锚杆模型,模拟拔出数值实验结果表明较快拔出速率将影响锚杆变形能力。

     

    Abstract: Loading transfer mechanism of anchorages is essential in controlling the supporting ability of a fully-grouted rebar. Considering the complexity of loading transfer between rock and rockbolt, the shearing behavior along the bolt and the cementation materials is examined in laboratory. The results showed that the peak/residual shear strength and shear stiffness were increasing with the increases of mortar strength or normal stress. Besides, the increase of shearing load ratio would increase the peak shear strength and shear stiffness, but have less influence on the residual shear strength. By simplifying the shear stress versus slip distance curve into trilinear bond-slip model, the debonding at the anchorage could be expressed in three stages, such as strengthen, soften, and slipping. Numerical simulations on the crack initiations and propagations at the interface were carried out using discontinuous deformation analysis. The results illustrated that the tensile damage was the major failure mode at the initial loading, followed by tensile-shear mixing modes near the peak value. After that, the shear behaviors were associated with the friction and the shape of the particles. By introducing the tri-linear bond slip features into the fully-grouted rebar model to simulate the coupling at anchorages, the results showed the deformability of the rebar would be reduced greatly when the ratio of pullout loading was higher.

     

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