Analysis and control technology of roof subsidence in non-pillar gob-side entryretaining formed by roof cutting and pressure release

In order to control roof subsidence in non-pillar gob-side entry retaining formed by roof cutting and pressure release,the evolution process of the surrounding rock structures and transfer mechanism of the overburden loads around the retained entry were analyzed based on the principle of gob-side entry retaining formed by roof cutting and pressure release.According to the motion characteristics and structure behaviors of the entry surroundings,it was obtained that the roof subsidence was mainly composed of the given deformation of the main roof and the separation of the cutting roof.Also,a theoretical calculating formula of the given deformation was derived by stablishing mechanical model for the entry surroundings.Besides,the relationship between the subsidence and the mining height and the cutting height were discussed in the study.Finally,based on the theoretical analysis,some specific strategies were proposed to control the roof subsidence.Depending on engineering geological conditions in No.117 mining face of Ruineng Coal Mine,theoretical calculation results showed that the subsidence of roof near the goaf and away from the goaf was 319.5 mm and 106.5 mm separately,which was basically consistent with the field measurement results.The research results could provide references for the analysis of surrounding rock movement and control in non-pillar gob-side entry retaining formed by roof cutting and pressure release.