CHEN X X, HAN W Y.Study on the deformation mechanism of prone to caving roof in roadways with top coal and the control technology of advanced pipe pre-grouting[J].Journal of Henan Polytechnic University(Natural Science) ,2024,43(4):1-11.

doi:10.16186/j.cnki.1673-9787.2023040010

Received:2023/04/06

Revised:2023/05/06

Published:2024/07/05

Study on the deformation mechanism of prone to caving roof in roadways with top coal and the control technology of advanced pipe pre-grouting

CHEN Xiaoxiang1,2, HAN Wenyu1

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

Abstract: Objectives To explore the deformation and failure mechanism of the roof of the roadway with top coal in thick coal seams in areas prone to caving，and to control the roof of the roadway with top coal in such areas， Methods The belt roadway of the 2701 working face of Changcun Coal Mine was taken as an example，the cause of the roof fracture of the roadway with top coal was analyzed through the theory of uniform beam.The conclusion was that the stability of the roof of the roadway with top coal was closely related to the width of the roadway and the strength of the top coal.The calculation formula for the displacement of the roadway side was obtained through the limit equilibrium criterion，proving that the roof and sides of the roadway with top coal had a synergistic deformation mechanism.By establishing a numerical model for the roadway with top coal，the relationship between the stability of the surrounding rock of the roadway with top coal and different roadway burial depths，lateral pressure coefficients，top coal thickness，and top coal strength was studied. Results The research results indicated that the greater the burial depth of the roadway was，the greater the impact on the stability of the two sides of the roadway with top coal was.The increase in the lateral pressure coefficient had a greater impact on the two sides of the roadway and the amount of floor heave，but had a smaller impact on the roof.The amount of roof subsidence was positively correlated with the thickness of the top coal，while the amount of floor heave was negatively correlated with the thickness of the top coal.The increase in the strength of the top coal caused a linear decrease in the subsidence of the roadway roof and the displacement of the two sides，while the amount of floor heave remained basically unchanged. Conclusions Based on the power-law cement grouts column seepage grouting diffusion theory，the advanced duct grouting radius was obtained，and the combined control technology of advance pipe pre-grouting and roof support for the roadway with top coal was proposed.The roof caving of roadways with top coal prone to slicing caving was successfully controlled，providing a reference for roof control of roadways with top coal under similar geological conditions.

Key words:thick coal seam;roadway with top coal;fracture mechanism of roof;advanced pipe;pre-grouting;combined control technology of roadway side and roof