The Bearing Performance and Sectional Design Method of Yielding U-Shaped Steel Support

The bearing capacity and yieldable performance of yielding U-shaped steel support are difficult to be fully exerted in roadways under complex conditions, and serious deformation and damage occur frequently. Taking the mining roadways of Tangkou Coal Mine in a kilometer-deep well as the engineering background, this paper summarizes and analyzes the typical failure modes of the on-site yielding U-shaped steel support. By utilizing the independently developed full-scale arch frame test system, the bearing performance tests of arch frames with different sectional methods were carried out. The results show that compared with the three-section U-shaped steel support, the yieldable performance of the four-section support is increased by 21.8%, while the bearing capacity is only decreased by 1.9%. Furthermore, numerical tests on yielding U-shaped steel support under different load patterns and different cross-sectional forms were conducted to clarify the deformation characteristics and internal force distribution laws of U-shaped steel support under complex stress conditions. Finally, a sectional design method for yielding U-shaped steel support and on-site engineering suggestions were put forward. Based on this methodology, it is feasible to optimize the support structure scheme that better matches the engineering geological conditions, thereby fully utilizing the yielding characteristics and load-bearing capacity of the support. This approach effectively prevents premature local failure of the support, extends its service life, and enhances the safety of roadway support engineering while achieving significant economic benefits.