Reasonable parameters for pre-filling and non-pillar mining walls

WANG Bingjian; WANG Yabin; LIU Yucheng; GUO Jiaxin

doi:10.11799/ce202503002

Abstract：In order to fundamentally solve the interference between the traditional goaf supporting construction process and the mining operation,and improve the coal recovery rate in the mine area of Wulan Setai Coal Mine,we proposed the in-roadway pre-filling and non-pillar mining and entry retaining technology.On the basis of analyzing the principle of the technology,a mechanical model was established.It is calculated that the support resistance required to cut the upper part of the goaf-filling wall is 19.2 MPa,and the reasonable width range of the goaf-filling wall is 0.14～2.58 m.Numerical simulation results indicate that during the process of increasing the wall width from 1.0 m to 3.0 m,the supporting stiffness of the wall gradually increases along with the width,resulting in a"consolidation hardening effect"that enhances the load-bearing capacity of the wall.Both the deviation of the wall towards the roadway and the overall deformation of the surrounding rock of the reserved tunnel show improvements,albeit with a diminished effect as the width increases.After comprehensive consideration of the wall support safety factor and the practical requirements of the section,the width of the pre-filled wall was determined as 2.0 meters,with a choice of C25 grade concrete for the backfilling material.Field practice has confirmed the rationality of the selected parameters.