ABSTRACT
Considering the complicated geological environment, the traditional bolt, which is supposed to provide anchorage force, is insufficient to resist large instantaneous impact under the dynamic load due to the constraints of its materials and design, causing the lack of deformation and absorbed energy. In this study, we developed a novel recoverable energy absorption bolt (RDEA bolt) that could defend against large explosion damage by offering enough deformation and absorbed energy compared with the traditional bolt. The static load tensile tests of the key components and the RDEA bolt's overall structure were implemented to analyze its constant resistance. Also, according to the inner structure of the RDEA bolt, the anchor system was simplified and became a problem of thick-walled cylinders for elastic-plastic mechanical analysis. Besides, the plane strain hypothesis was introduced, and the constant theoretical resistance was calculated by the classical two-dimensional Lame equation. The theoretical value of the RDEA bolt was compared with the experimental result. The theoretical value of the RDEA bolt constant resistance is 13.62 KN, the experimental value is 12.81 KN, and the difference is 0.81 KN. It was shown that the two values were within the reasonable error range, which could confirm that the analytical model of elastic-plastic mechanics is effective and useful. Furthermore, the constitutive energy equation was deduced and verified based on the load-displacement curve obtained from the static load tensile test. The results confirmed that the RDEA bolt could support adequate deformation and energy absorption and provide a design to optimize the traditional bolt that could respond to large explosion damage, which may also inspire deeper and more promising research on underground protection.
