Effect of Stiffeners on the Bearing Capacity of Steel Support Cutting Pipe Structure

A novel pipe roofing structure used in underground engineering, steel support cutting pipe method (SSCP), was introduced in this investigation. In this method, large-diameter steel pipes connected by steel plates and H-shaped steel supports are used as pre-support. Besides, steel pipes are supported by stiffeners. This investigation aims to analyze the effect of stiffeners on the ultimate bearing capacity of SSCP structures through a combination of tests and numerical simulations. The results indicated that the specimen began to yield when the external load reached 70% of the ultimate bearing capacity, and the arrangement of stiffeners increased the ultimate bearing capacity of SSCP structure by 50.0%. The SSCP structure had the highest ultimate bearing capacity when the stiffener's chord-to-height ratio is 0.24. Besides, the ultimate bearing capacity increased linearly with the increase of the stiffeners' number and thickness. Finally, the number and thickness of stiffeners were optimized using the fuzzy mathematical theory. Subsequently the optimum ratio was obtained, that is, the stiffener arrangement distance: steel pipe diameter is 0.62, and stiffener thickness: steel pipe diameter is 0.018.