Research on the fluid-structure interaction mechanism and reasonable width of coal pillar in gob-side entry driving
HAO Wei
Abstract：The failure of the section coal pillar due to the coupled effect of mining disturbance and water seep-age weakening is a significant contributor to water inrush accidents in roadways.Exploring the instability char-acteristics and optimal width of the section coal pillar is crucial for effective mine water prevention and control.This paper focuses on the study of the coal pillar in the gob-side entry driving section of the water-bearing goaf area.A fluid-structure interaction numerical calculation model of the section coal pillar is established u-sing FLAC3D,which reveals the coupled characteristics of stress,plastic zones,and water seepage zone within the coal pillar under the influence of mining,water immersion weakening,and roadway excavation.Additional-ly,the stability characteristics of coal pillars with varying widths are compared.The results show that:Under the superimposed effect of overburden pressure and water pressure from the goaf,the coal body on the water-immersed side of the coal pillar is the first to fail.As water accumulates and infiltrates,the elastic modulus,co-hesion,and internal friction angle of the coal body in the water seepage zone decrease correspondingly.The lifecycle of the coal pillar can be divided into three stages:"mining of the upper working face,infiltration of water from the goaf,and roadway excavation."Based on this,it is proposed that the connection between the plastic zone and the water seepage zone should be considered the critical condition for the coal pillar.When the width of the coal pillar is 3 m and 5 m,the plastic zone connects,forming a water conduction channel.However,when the width of the coal pillar is 7 m,9 m,and 11m,the water seepage zone does not connect to the plastic zone,and the coal pillar maintains bearing and water-resisting characteristics.Finally,after emplo-ying a 7 m coal pillar in the field,the maximum roof subsidence observed is 146 mm,demonstrating effective roadway control.
Keywords：fluid-structure interactiongob-side entry drivingwater immersion softeningcoal pillarnumerical simulation
Publication Date：2025-10-30
Online Publishing Date：2025-11-06(First online date of this platform, not the publication date of the document)
Pages：9( 14-22 )