Analytical Model for Predicting Stress Distribution and Load Transfer of Tension-Type Anchor Cable with Borehole Deviation

Abstract

Borehole deviation is a common problem in anchor cable engineering of soil and rock, especially in long drilling holes, which affects the reinforcement effect of tension-type anchor cables, but the law of stress distribution and load transfer of anchorage section with borehole deviation is still not systematic or comprehensive. The research presented in this paper established an analytical model to determine the axial force and shear stress distribution and load transfer of linear and bending anchorage sections by using elastic mechanical analysis. A comparison of axial force and shear stress distribution and load transfer mechanic behavior of linear and bending anchorage sections was made, and the effects of tensile loading, anchorage segment lengths, bending radius and borehole diameters were calculated and analyzed. In addition, an indoor model test was carried out to validate the theoretical calculated results. The results from the theoretical analytical model and the indoor model test had good consistency, which indicated that: (i) the decay speed of axial force and shear stress on the bending anchorage sections was slower than on the linear ones, so a longer anchorage section length (about 23%) was needed when borehole deviation occurred in soil and rock engineering; (ii) the tensile loading, anchorage segment lengths, bending radius, and borehole diameters affected the axial force and shear stress values, reasonable stress distributions, the inner- and outer- surfaces ratios or all of these mechanic behaviors. The deduced analytical model can be used to calculate and predict the mechanic behavior of stress distribution and load transfer of linear and bending anchorage sections in anchor cable engineering.