Numerical analysis of the influence of coal pillar size on auxiliary tunnel stability

It is very important to study the stability of tunnel in area affected by mining activities. In particular, choice coal pillar size has a direct influence on these tunnels. The authors this used Flac3D program model face LC1 with various sizes. 220 m-long known as 20 degrees rock mass layers. studied pillars are widths at 5 m, 8 10 15 and 30 m. highest vertical stress maximum horizontal placed different locations along lower (LC2), shown results numerical simulation. pressure distribution tunnel's top level concentration its two sides asymmetrical for inclined seam conditions. position tension expected change from left hip side widens. This essentially marks system's transition one stable state another. Due mass's weak during transition, support must be strengthened order improve stability.