Analytical solution for pre-press transfer effect of bolt composite member

Abstract

In order to study the pre-press transfer effect of bolt composite member, assume that the roadway surrounding rock is elastic foundation, take the roof as an example, the elastic foundation beam model of the roof which is supported by pre-stress bolt composite member was established. Based on the superposition principle, combining with boundary conditions, the deflection equation of the model was obtained. Combined with engineering examples, results show that deformation coordination coefficient β is an important parameter which affects the transmission of bolt pre-stress. The smaller β is helpful for the uniform transmission of bolt pre-stress. Increasing bending stiffness of the belt can deduce β and improve the effect of support. In the condition of different bolt arrangements, the distribution of roof counterforce is mainly influenced by end effect and superposition effect. The counterforce is higher at the end of the belt by the influence of end effect while higher at the middle of the belt by the influence of superposition effect. Optimal arrangement of bolt can be determined through the balance of end effect and superposition effect.

Keywords

• elastic foundation beam
• bolt support
• pre-stress
• roof counterforce
• roadway support