Stability Analysis of Bolts Reinforced Rock Jointed Slope by Considering the Transverse Effects

Abstract

The fully grouted bolt is a convenient, effective, and economic technology for slope reinforcement. A new nonlinear Hoek-Brown strength reduction method based on the characteristics of a jointed rock mass is proposed. By analyzing the change in slope failure mode, effects of the bolt head, spacing, inclination, and arrangement on the stability of the slope are investigated. Results show that the shear strength of the bolted structure is contributed by the axial force and transverse shear force. The transverse shear force of bolts increases the slope stability and improves the bolt bearing capacity; the bolt head is important in determining the failure mode and factor of safety of a bolted slope, while the size and material parameters of the bolt head are not important when the size of the bolt head is sufficiently large. The vertical bolt spacing has a nonlinear effect on the slope safety factor, and the failure mode of the slope changes from deep sliding to partial deformation along the joint surfaces with increase in the bolt horizontal spacing. With increase in the bolt inclination angle, the safety factor first increases and then decreases, and the maximum safety factor occurs when the bolts are placed horizontal or perpendicular to the slip surface. The slope safety factor decreases with decrease in the bolt length. An optimal design of longer bolts at the bottom and shorter bolts at the top is recommended. A shear zone forms from the intersection of two joints to the slope surface in the upper part of the slope.