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张拉条件下锚固剂-围岩界面剪应力分布规律研究

Research on distribution law of interfacial shear stress between surrounding rock and anchorage agent under tension condition

  • 摘要: 为研究锚固剂-围岩界面剪应力分布规律,基于锚杆、锚固剂复合体与围岩孔壁间三阶段线性函数剪切滑移模型,采用载荷传递法开展理论分析,推导出弹性阶段锚固剂-围岩界面剪应力分布公式。结果表明,张拉承载条件下界面剪应力极大值出现在锚固段外端口且沿锚固长度方向呈单调递减规律分布。当锚固段长度较小时(≤0.3 m),界面剪应力可近似认为是均匀分布的。随着锚固长度的增加,锚固段外端口最大剪应力值逐渐降低,界面剪应力分布不均匀程度增加。适当增加锚固长度可以整体降低锚固段界面剪应力大小,一定程度避免锚固始端界面剪应力达到抗剪强度而发生滑移滑脱失效。采用FLAC3D软件开展锚杆、锚固剂实体单元数值计算,验证了锚固剂-围岩界面剪应力沿锚固长度呈递减分布的规律,发现剪应力在锚固段始端前1/3位置递减明显。

     

    Abstract: In order to research the distribution law of shear stress on anchorage agent-surrounding rock interface,the shear-slip model of three stage linear function and load transfer method were used,the formula of the shear stress distribution law at elastic stage is derived.The results show that the maximum shear stress appears on the external port of anchorage section and monotonically decreasing along anchorage length under tension loading.When the anchorage length is small (less than 0.3 m),the interfacial shear stress can be considered as uniform distribution.With the increase of anchorage length,the maximum shear stress at the beginning of anchorage section gradually decreases,and the degree of irregularity of interfacial shear stress increases.Properly increasing anchorage length can reduce the interfacial shear stress of anchorage segment,and avoid the slipping slippage failure of anchoring initial shear stress at a certain extent.The FLAC3D software is applied to carry out the numerical calculation of the anchorage solid unit.It is verified that the shear stress of the anchorage agent surrounding rock interface is decreasing along the length of anchorage.It is found that the shear stress decreases obviously at the beginning of anchorage 1/3.

     

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