Abstract:
To facilitate the practical application of fiber-reinforced polymer (FRP) strengthened structures and improve the bearing capacity and deformation capacity of coal pillar in goaf, the mechanical performance of carbon fiber-reinforced polymer (CFRP) uniformly wrapped coal columns under axial compression was explored. Test results show that its state is basically unchanged and the fracture position is about 0.25-0.5 times the height of CFRP confined coal columns, and the axial deformation capacity is increased by at least 1.5 times when the coal columns are damaged since the uniform confinement of CFRP. The peak strength of single and double CFRP confined coal columns is increased by 3.56-6.34 times and 6.33-11.21 times, respectively. When the number of CFRP layers is the same, the strength enhancement ratio of CFRP confined coal columns decreases gradually with the increase of loading rate, and the decrease trend becomes more significant with the increase of the number of CFRP layers. The effect of CFRP layers on peak strength is more significant than that of loading rate, but it is obviously the opposite as for the failure time. It has been obtained that the 3D visualized mapping function of strength enhancement ratio considering loading rate and number of CFRP layers. The modified Richart strength model of CFRP confined coal columns has been established, and the index of integral absolute error shows that the model has good performance and higher precision.