Analytical model of shear behaviour of a fully grouted cable bolt subjected to shearing

Abstract

A fully grouted cable bolt is normally loaded at rock joints by a combination of the axial and shear forces causing both axial extension and shear deformation of the cable. The proposed analyses presented here attempts to predict the joint shear strength and shear displacement. The analyses are based on the statically indeterminate beam theory and some basic findings and conclusions of other researchers. Parametrical investigation is performed on four influence factors including bolt pretension, joint friction angle, concrete strength and bolt installation angle. Although the true plastic moduli of the cable bolt deflecting section at failure are the essential parameters in this analysis, they are practically impossible to determine. Thus, the average cable moduli obtained from the cable tensile strength tests were used. The proposed analytical model was compared with the experimental results, showing a good agreement. This analytical work aims to develop a simple tool for the practicing geotechnical engineer to effectively evaluate the cable shear behaviour and the influence of fully grouted cable bolts on joint shear resistance. Cable bolting reinforcement is currently considered to be one of the best methods for 6 improving rock strata conditions and to control the strata movement and deformation. A fully 7 grouted cable bolt is normally loaded at rock joints by a combination of the axial and shear 8 forces causing both axial extension and shear deformation of the cable. The axial and shear 9 loads experienced by cable bolts are very complex as they are influenced by many factors, 10 such as cable strength, cable moduli, cable dimensions, rock strength, and joint properties. Disciplines Engineering | Science and Technology Studies

Load Transfer Characteristics of a Cable Bolt in DEPT

“…Direct shear restraint and high normal stress are applied by bolt to fracture surfaces to minimize their displacements. is mechanism allows excavation surfaces to stabilize and makes them self-supporting [4,5]. In order to mobilize the shear restraint and high normal stress, loads have to be effectively transferred between cable bolts and rock masses mainly via the grout anchorage [6].…”

An analytical model for shear behaviour of bolted rock joints

“…The gradual decrease of the foundation stiffness in the elasto-plastic stage can be described by Eq. (22). In the plastic stage, the foundation stiffness is assumed to reach a residual value and remains constant afterwards:…”

Experimental Study on Shear Behavior and Failure Mechanism of Bolted Heterogeneous Rock Joints under Different Anchorage Conditions

“…Numerous of rock engineering applications such as civil and mining engineering projects have proved that the instability and integral failure of the rock mass have great correlations with extensions and propagations of weak discontinuities [15]. The reinforcement for jointed rock mass using rock bolts has always been one of the most effective and economical geo-structural reinforcing technologies widely used in rock engineering projects for more than 100 years since 1913 in Germany [16][17][18][19][20][21]. However, instability of anchored rock mass caused by bolt failure often occurs [21][22][23].…”