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

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.