An analytical model of the load transfer behavior of fully grouted cable bolts

An analytical model for the behaviour of fully grouted cable bolts under axial loading condition is provided in this paper. This theoretical approach considers the elastic, softening and debonding behaviour at the cable/grout interface using a tri-linear model. Input parameters include the mechanical properties of the confining medium, grout and the cable bolt. With this model, the maximum load transfer capacity of both plain strands and modified cable bolts were studied. Laboratory tests using a standard plain seven-wire strand and MW9 cable bolts were used to validate this analytical model. The results show a good correlation between the test and model simulation. The shear stress distribution along the full length of the cable/grout interface when peak load occurring was also investigated, indicating the shear stress can be regarded as uniform if the embedment length is short. Nevertheless, for cable bolts with long embedment length, the non-uniform shear stress distribution along the interface is more apparent. The shear stress propagation along the cable/grout interface was also analysed in the full pull-out process. Modelling results show that the shear stress from the loaded to the unloaded end gradually reaches the interfacial shear strength. (C) 2015 Elsevier Ltd. All rights reserved.