Structural Optimization Of Steel Strand Anchorage And Development And Research Of FRP Anchor Ring

Steel strand cable anchor supporting is widely applied to coal mine supporting system, and single-bore anchorage device is the key part of anchor cable supporting structure. To improve the load-carrying properties of metal anchorage device, the optimization calculation is conducted to the match of taper angles of clamping piece and anchor ring with numerical method. We design temporary anchorage structure which has a ceramic ring and can be easily removed, and conduct numerical modeling and perform compression test on this structure. To prevent metal anchorage device’s rusting and corrosion failure in high-tension and permanent anchorage structure, we design a composite anchor ring with continuous glass fiber filament winding unsaturated polyester resin matrix, and perform compression and stretching experiments to study the load-carrying properties of these anchor rings, and we analyze their loading features and failure mode by using finite element analysis,and verified results through tests.The research results of this paper show as below:Different match of taper angles of anchor ring and clamping piece of single-pore steel strand anchorage device can influence its load-carrying properties. When taper half angle of clamping piece is 7° and taper half angle of anchor ring is 6.5°~6.8°, the uniformity coefficient of the stress distribution of anchorage device will have a high performance and the load-carrying properties of anchorage device can be improved obviously.The design of coal mine temporary anchorage structure with Al2O3 ceramic ring proposed a new method to help remove the anchorage structure. Numerical calculation proves load-carrying properties of ceramic ring in this anchorage structure to be good, and when circumferential tensile force reaches up to ultimate strength, in the middle of outer face of ceramic ring the mode of axial direction failure will happen. To design ceramic ring’s size, the security coefficient of tensile stress will be set more than 2.0 if the processing faults of ceramic ring is considered.GFRP anchor ring, which has the alkali-free glass fiber as wild phase and unsaturated polyester resin as matrix and filament winding as forming processing, can replace metal anchor ring to prevent the anchorage failure for rusting and corrosion. The load-carrying property of produced GFRP anchor ring is above 500 kN, and the limit of tensile stress is 464 k N.From the loading analysis of GFRP anchor ring with the help of ABAQUS software, we found that the load-carrying property of circumferential fiber in anchor ring has a high performance; small scale crack in the matrix caused by tensile stress in contact surface between anchor ring and clamping piece cannot influence the load-carrying property anchor ring; shearing stress in the plane of symmetry of GFRP anchor ring is the main factor if it exceeds material’s horizontal load-carrying limit in a large scale; GFRP anchor ring’s design angle of 6.3° to 6.5° can improve anchorage device’s load-carrying property when the angle of clamping piece is 7°. The validation test results showed that stretch-draw ultimate strength of 6.3° GFRP anchor ring is 512 kN. The results obtained from the FEM analysis and the test coincided very well, which proved that the finite element analysis is reliable.