Mechanism and application of new prestressed yield bolt for controlling deep high-stress rock mass

Abstract

The elastic elongation of the bolt itself is insufficient to meet the surrounding rock deformation in deep high-stress roadway, resulting in a large number of breakage of the bolt and the instability of the surrounding rock. Aiming at this problem, this paper proposed a new prestressed yield bolt with the engineering background of Shangping roadway in Huafeng Coal Mine. Based on the analysis of instability of Shangping roadway surrounding rock, the structure, characteristics and mechanical properties of the prestressed yield bolt was investigated. The yielding properties and deformation process of different yielding members were researched in detail. According to the engineering background, the yielding support scheme were designed and applied. The results showed that the yielding effect of yielding pipe was more obvious than that of the wooden pallet. The yielding load, the maximum yielding deformation, the yield stability coefficient of the designed yielding pipe were 190 kN, 25 mm, 1.6 kN/mm, respectively. The stability forces of the bolts in the roof, the top corner of the right side and the bottom corner of the left side of the roadway were almost the same. The overall deformation of the roadway controlled by the yielding support scheme was not large. So, the yielding pipe protected the bolt-rod from being damaged due to excessive deformation, thereby realizing the yield bolt to control the stability of the roadway surrounding rock for a long time.