Research on deformation characteristics and control technology of surrounding rock for gob‐side entry with small coal pillar in gently inclined coal seam

• Published in: Energy science & engineering 2024-04, Vol.12 (4), p.1759-1774
• Main Authors: Wang, Beifang, Zhou, Duo, Zhang, Jing
• Format: Article
• Language: English
• Subjects: cause analysis; control technology; deformation characteristic; gently inclined coal seam; gob‐side entry
• ISSN: 2050-0505; 2050-0505
• DOI: 10.1002/ese3.1707

With the engineering background of the gob‐side entry of panel SA1104 in Heiyanquan Coal Mine, the deformation characteristics and control technology of the surrounding rock for gob‐side entry with small pillar in gently inclined coal seam have been studied by field observation, numerical simulation, and theoretical analysis. The study show that: (1) The surrounding rock has obvious asymmetric deformation characteristics, the roof subsidence on the solid coal side is larger than that on the small coal pillar side; the deformation of small coal pillar side rib is more significant than that of the solid coal side rib, which is concentrated in the middle and upper part, and slip deformation occurs at the upper sharp corner; the middle part of solid coal side rib exhibits prominent deformation; and floor heave is shifted to the small coal pillar side. (2) The stress concentration zone on the small coal pillar side is located 1.9 m from the high rib, while the stress concentration zone on the solid coal side is located 4.1 m from the low rib. The difference in the rib‐to‐rib peak stress is 4.2 MPa, and the stress concentration on the solid coal side is larger than that on the small coal pillar side. (3) Poor physical and mechanical properties of the surrounding rock, high in‐situ stress, and high deterioration degree of the surrounding rock structure are the main internal causes of the entry deformation; strong mining disturbance, arbitrary support parameters, and large section sizes are the main external causes of the entry deformation. (4) The asymmetric combined support program is proposed, featuring “non‐equidistant cable + inclined bolt on the roof, bolt extension + cable supplement on the small coal pillar side rib, and bolt encryption on the solid coal side rib”, and it had a positive on‐site application effect. The asymmetric deformation characteristic and stress evolution of entry are analyzed. The internal and external causes of entry deformation are explained. A asymmetric combined support method of “bolt + steel wire mesh + rebar ladder beam + cable” is proposed, and it has a positive on‐site application effect.