Numerical simulation of fully grouted rockbolts by considering nonlinear bond-slip behaviour

摘要

In most rock engineering projects,a fully grouted rockbolt system is the primary support for reinforcing unstable rock strata.A better understanding of the characteristics of the load transfer mechanism between rockbolts and rock mass could lead to a significant improvement in the performance of rockbolts.Previous studies have pointed out that the bond-slip relationship between rockbolts and the rock mass is nonlinear and hence the bond-slip model in Fast Lagrangian Analysis of Continua(FLAC2D)could not adequately represent the nonlinear behaviour of rockbolts.In this study we numerically modelled the behaviour of fully grouted rockbolts subjected to tensile loads by implementing a nonlinear bond-slip relationship for the bolt-grout interface into FLAC2D.The proposed numerical model was verified by pull-out tests on rockbolts.The findings show that the modified rockbolt model in FLAC2D is capable of capturing the nonlinear shear bond stress behaviour.