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刘广建, 裘伟奇, 罗战友, 王志成, 周浩, 陈曦. 考虑锚杆强度的加锚岩体结构面锚固效应试验研究[J]. 岩土工程学报. DOI: 10.11779/CJGE20231135
引用本文: 刘广建, 裘伟奇, 罗战友, 王志成, 周浩, 陈曦. 考虑锚杆强度的加锚岩体结构面锚固效应试验研究[J]. 岩土工程学报. DOI: 10.11779/CJGE20231135
Experimental Study On Bolting Effect Of Bolted Joint Rock Masses Considering Bolt Strength[J]. Chinese Journal of Geotechnical Engineering. DOI: 10.11779/CJGE20231135
Citation: Experimental Study On Bolting Effect Of Bolted Joint Rock Masses Considering Bolt Strength[J]. Chinese Journal of Geotechnical Engineering. DOI: 10.11779/CJGE20231135

考虑锚杆强度的加锚岩体结构面锚固效应试验研究

Experimental Study On Bolting Effect Of Bolted Joint Rock Masses Considering Bolt Strength

  • 摘要: 锚杆强度主要受其直径和材料(抗拉强度)的影响,锚杆强度的大小对提高加锚岩体结构面抗剪力至关重要。开展了加锚结构面剪切试验,研究了锚杆强度对加锚结构面剪切变形特征及锚固效应的影响,提出了考虑锚杆强度的加锚结构面抗剪力计算模型,分析了不同锚杆强度下锚杆轴力与剪力对结构面抗剪力贡献情况。研究表明:(1)随着锚杆直径的增加,加锚结构面峰值抗剪力呈线性增长趋势;锚杆直径超过一定临界值后才会发挥锚固作用,锚杆抗拉强度越大临界值越小。(2)随着锚杆直径和抗拉强度的增大,锚杆塑性铰外移,变形段长度增加,锚杆抵抗变形破坏的能力增强,对结构面抗剪力的提升增强。(3)加锚结构面剪切过程可分为弹性、屈服、强化和残余四个阶段。弹性和屈服阶段,锚杆主要发挥销钉作用,锚杆的贡献与锚杆抗拉强度呈正相关,与锚杆直径的关系受到锚固剂厚度影响;强化阶段,锚杆形成塑性铰,锚杆的贡献由锚杆抗剪力和轴力共同提供,与锚杆抗拉强度和直径呈正相关;残余阶段,锚杆断裂不提供抗剪力。(4)基于锚杆大变形理论,提出考虑锚杆强度的加锚结构面抗剪力模型,分析可知随着锚杆直径和抗拉强度的增加,锚杆轴力贡献占比不断增加,锚杆剪力贡献占比不断减小。

     

    Abstract: The strength of bolt is mainly affected by its diameter and material (tensile strength). The strength of bolt is very important to improve the shear resistance of bolted joint rock masses. The shear test of bolted joint was carried out. The influence of bolt strength on the shear deformation characteristics and bolting effect of bolted joint was studied. The calculation model of shear resistance of bolted joint considering bolt strength was proposed, and the contribution of axial force and shear force of bolt to shear resistance of joint under different bolt strength was analyzed. The results show that:(1) With the increase of the bolt diameter, the peak shear resistance of the bolted joint increases linearly. When the bolt diameter exceeds a certain critical value, it will play a bolting role. The greater the tensile strength of the bolt, the smaller the critical value. (2) With the increase of the diameter and tensile strength of the bolt, the plastic hinge of the bolt moves outward, the length of the deformation section increases, the ability of the bolt to resist deformation and failure is enhanced, and the shear resistance of the joint is enhanced. (3) The shear process of jointed joint can be divided into four stages: elasticity, yield, strengthening and residual. In the elastic and yield stages, the bolt mainly plays the role of pins. The contribution of the bolt is positively correlated with the tensile strength of the bolt, and the relationship with the bolt diameter is affected by the thickness of the anchoring agent. In the strengthening stage, the bolt forms a plastic hinge, and the contribution of the bolt is provided by the shear resistance and axial force of the bolt, which is positively correlated with the tensile strength and bolt diameter. In the residual stage, the bolt fracture does not provide shear resistance. (4) Based on the large deformation theory of bolt, the anti-shear force model of bolted joint considering the strength of bolt is proposed. The analysis shows that with the increase of bolt diameter and tensile strength, the proportion of axial force contribution of bolt increases, and the proportion of shear force contribution of bolt decreases.

     

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