Study on layout optimization of seam gateway under contiguous seams

Meng Hao

doi:10.13199/j.cnki.cst.2016.12.008

Abstract：In order to set up the rational layout location of the seam gateway under the downward mining in the contiguous seams,a numerical simulation,theoretical analysis,floor frictional experiment and site test method were applied to the analysis on the floor stress distribution law of the remained coal pillar,stability of the sectional coal pillar,surrounding rock deformation failure features of the gateway and others.The study showed that No.l0 seam mining caused the floor failure depth spread to the level of No.11 seam gateway.The stress reduced zone had a horizontal distance of 7 m to the retained coal pillar in the upper seam mining.Influenced by the secondary mining,the failure width of the sectional coal pillar in No.11 seam was about 4 m and the rational inner offset distance in the gateway layout should be over 11 m.When the inner offset distance of 14 m and 20 m applied to the gateway layout in the simulation experiment,the surrounding rock could keep a same degree good stability.In order to improve resource mining rate,the inner offset distance of 14 m selected could ensure a safety mining operation.Finally a monitoring and measuring on experiment section was conducted in No.1113 coal mining face and inner offset distance of gateway was selected as 15 m conservatively.The site measurement results showed that under the layout condition,the stability of sectional coal pillar was good,the convergence between two sidewalls along the gateway was 30～220 mm,the convergence between the roof and floor was 20～ 110 mm and the surrounding rock deformation of the gateway could be well controlled.