doi:10.16186/j.cnki.1673-9787.2023030063

Received:2023/03/26

Revised:2023/04/25

Published:2024/05/15

Research on the mechanism of coal rib spalling in large mining height faces in soft coal seams and the technology of alternating deep and shallow hole advance pre-grouting reinforcement

CHEN Xiaoxiang1,2, HAN Wenyu1

1.School of Energy Science and Engineering，Henan Polytechnic University，Jiaozuo  454000，Henan，China；2.Henan Province Collaborative Innovation Center of Coal Work Safety，Jiaozuo  454000，Henan，China

Abstract: Objectives In order to explore the mechanism of coal wall spalling in large mining height workfaces of soft coal seams and effectively control serious rib spalling in the large mining height workface of soft coal seams.  Methods Based on the theory of material mechanics，the frequent locations of rib spalling were obtained，and the criterion of coal wall shear failure was introduced to determine the main controlling factors of soft rib spalling.The 1305 mining face of Licun Coal Mine is taken as an example，and a numerical model is established through FLAC3D.The maximum displacement of the coal wall，the depth of coal failure，the magnitude of abutment pressure，and the position of peak abutment pressure are taken as parameters for comparison.Through the orthogonal test research method，the influence degree of coal seam burial depth，internal friction angle，cohesion，tensile strength and support strength on rib spalling is studied.  Results The research results show that the physical and mechanical properties of coal （internal friction angle and cohesion） are the main factors affecting rib spalling，and the occurrence condition of coal （burial depth） is also a key factor.Based on the orthogonal test results，the paper proposes the technology of deep and shallow hole alternating advance pre-grouting reinforcement for the fully mechanized caving face with large mining height.  Conclusions The technology effectively controls the serious situation of rib spalling in the 1305 mining face of Licun Coal Mine through fault tectonic belt，which could provide a reference for the control of rib spalling in other fully mechanized caving faces with large mining heights with similar geological conditions.

Key words:large mining height;soft coal seam;rib spalling;orthogonal test;numerical simulation