Physical model test study on support of super pre-stressed anchor in the mining engineering

With the increase in mining depths, support problems of anchor such as roof accidents and large deformation of soft rock are becoming more and more prominent. Whether the anchor is suitable for deep roadway support has been questioned. In order to explore this problem, this paper studies the ultimate support effect of super pre-stressed anchors. Based on current higher prestress support technology in mining engineering, a support scheme of super anchor is proposed and investigated. In this work, the super anchor scheme and the other two schemes were compared and analysed through a physical model test. The model's displacement data was recorded by a high-speed camera. Meanwhile, the numerical model with the same conditions is calculated. The results show that, the super anchor scheme can improve the stress distribution of the surrounding rock; and this method contributes to the optimization of the support parameters and improves the roof bearing capacity. In addition, the super anchor scheme has a smaller scope of damage than the other two schemes. Third, the super anchor scheme reduces the number of anchors without reducing the strength of the support, which is beneficial to the rapid excavation of the roadway. However, it is worth noting that, the end of the super anchor will produce significant stress concentration in the support process, and this easily leads to the separation and crack of the roof near the end of the super anchor. In short, the physical model test shows that, using super pre-stressed anchors is promising for solving the extremely difficult deep roadway support problems.