Study on deformation mechanism and supporting method of large section soft surrounding rock chamber in underground mine

The support of large-section broken and weak surrounding rock chambers has always been a problem in underground mining.Based on the tickler, this paper takes the large deformation of the chamber of the Lannigou gold mine in Guizhou as the engineering background, through field measurement data, theoretical calculations, and geological environment analysis to reveals the deformation mechanism of the floor and sidewalls.Under high vertical and horizontal stress, the roadway presents the characteristics of a diamond-shaped spatial rupture composed of two sets of superior joints.Under the influence of mining blasting vibration, the stress of the surrounding rock is redistributed so that the plastic zone continues to expand to the depth, reducing the effect of supporting and anchoring force, resulting in serious deformation of the surrounding rock.Based on the support theory, this paper proposes that the roof adopts reinforcement anchor cable, grouting, and spray anchor net, the two sides adopt reinforcement resin anchor rod, anchor cable, wall thickness grouting, and spray anchor net, and the bottom plate adopts reverse arch, and grouting.According to the combined support method, the field test shows that this combined support method has a good effect on the long-term stability control of the chamber compared with the support method before.This research can provide a reference for the deformation and reinforcement of roadway under complicated deep geological conditions.