A prognostic model of side friction of rock bolt anchoring section based on associated flow law

Abstract

The distribution of side friction in the elastic stage can be obtained according to the Mindlin solution and its related derivative methods. Nevertheless, owing to the limitations of these methods, they cannot predict side friction in the plastic stage. In order to accurately and reliably characterize the distribution of frictional stress along the anchorage section of the interface plastic deformation side, at present, side friction in the plastic stage is mainly predicted by establishing a nonlinear bond-slip model. However, the physical meaning of some parameters in the existing bond-slip model is ambiguous, and these parameters need to be obtained by fitting measured data from the pull-out test, which cannot be solved directly according to actual working conditions. Since the expansion of soil around the anchor in the plastic stage meets the associated flow law, a new prediction model of side friction distribution in the plastic stage is established in this paper based on the rule. Compared with the measured data of several groups of tests and prediction results of the Mindlin solution, it is found that the model proposed shows good accuracy and stability in predicting side friction in the plastic stage.