A new analytical solution for the displacement of fully grouted rock bolt in rock joints and experimental and numerical verifications

Abstract This study proposes a new analytical solution to predict displacement of a fully grouted rock bolt intersected by single rock joint. The main characteristics of the analytical model, consider the bolt profile and joint movement under pull test condition. The anchorage capacity of fully grouted bolts has been studied for many years; however, the bolt profile and its effect on bolt shear resistance are poorly understood. Investigations of load transfer between the bolt and grout indicate that the bolt profile shape and spacing play an important role in improving the shear strength between the bolt and the surrounding strata. Rock displacement is a sum of elastic part and a jump part due to the presence of joints planes. The performance of the proposed analytical model is validated by experimental method and comparison with numerical modeling. The results showed that there is a promising agreement between analytical and numerical methods. Studies indicate that the displacement rate between the bolt and the rock declines exponentially. Which is dependent on the bolt characteristics such as: rib height, rib spacing, rib width and thickness grout, material and joint properties.