Static and dynamic mechanical properties of energy absorption bolts (cable) and field tests
摘要
In view of the failure characteristics and the special requirements of bolts used in bump-prone roadways, the energy-absorption anchor (cable) is invented. The energy absorption principle of the energy-absorption anchor (cable) is analyzed based on the plastic bending theory, and the static tension and impact tension tests are carried out by use of the independently designed static and dynamic loading test system. The test results show that the hex pipe of energy absorption anchor (cable) is squeezed and deformed, and then slip resistance for friction cylinder is produced during the whole tension process. The geometric parameters and the assembly forms of hex pipe and friction roller have important influences on the working resistance. Under whether static tension or impact tension, the load-displacement curves both consist of three stages, initial axial force growth stage, axial force stationary stage and axial force spurt-stationary stage. The rod body of anchor is basically in the elastic state at the axial force stationary stage, and the bolt begins to yield when the action of friction and sliding is completed. The energy absorption action of energy-absorbing structure delays or slows down the yielding of bolt effectively. Compared with the ordinary bolt, the energy absorption anchor (cable) possesses better self-protection and self-adaptability. The field tests show that the energy-absorption anchor (cable) can effectively weaken the effect of the impact energy acting on the surrounding rock of roadways.