Abstract:

In order to guarantee the support stability, tensile and creep properties of self-drilling anchor in rock and soil anchoring engineering, the strength of accessories and anchor should be matched. The numerical simulation analysis on stress and deformation of R32 nut and anchor under the axial load is carried out by ANSYS Workbench. The analytical results show that: (1) When the radial fit clearance is 0. 2 mm, the maximum force value of the coupling is basically located at the bottom of the first three coupling threads and the total deformation of model with 65 mm-long nut is only 0. 68 mm under 400 kN. (2) The deformation value when the fit clearance is 0. 5 mm increases by 97. 06% than that when the fit clearance is 0. 2 mm. It shows that the 50 mm-long nut has a large stress area in the whole length, the deformation runs through all threads, and there is a risk of failure by comparison of fitting condition with the 50 mm-long nut under the condition of 0. 2 mm fit clearance. The overall numerical analysis results indicate that the 65 mm-long nut and the fit condition of 0. 5 mm cannot meet the strong requirements of the system, while the fit clearance of 0. 2 mm can. The results are verified by the experiment and show the consistency with the analytical results. When the system is stretched, 90% of the samples show failure fracture at the bottom of the connection between the nut and the anchor, and the variation of the force value also conforms to the hardness test rule at the bottom of thread.

Key words: threaded connection, nut, self-drilling anchor, fit clearance, numerical analysis, Workbench