Structure Model of Roadway with Large Deformation and Its Basic Research into Engineering Theories

Original scientific paper With the increase in mining depths and the occurrence of worsening conditions, deep, large-scale and rapid mining may lead to more complicated dynamic features for tunnels, making them vulnerable to dynamic disasters such as rock bursts and coal/gas outbursts with subsequent heavy damage and casualties. A three-dimensional structural mechanics model for deep stopes was developed, and a dynamic disaster system model for deep mine tunnels was analysed and researched according to the catastrophe system theory; then the "large and small structural theory" of mining without coal pillars was presented, and a method for computing the range of "inner stress fields" was modified. At the same time, two structural mechanics models for tunnels, namely, "given deformation" and "finite deformation", were established and a new method of controlling dynamic disasters in tunnels is proposed. Such mining patterns can effectively absorb dynamic impact energy generated by the bending and fracturing of overlying strata. Research shows that in mining without coal pillars, large structures in the surrounding rock in the tunnel refer to strata within a "stress arch", while small structures refer to the roadside fillers, top coal, side coal, the immediate roof, baseboards and other anchoring structures, wherein the forces from the two above mentioned structures are sourced from the strata within the "stress arch", the roadside fillers force source is the fractured strata within the "breaking arch", and the side coal force source is the action of the strata within the "stress arch"; under the roadside filler mining pattern with reserved deformation, the load carrier (coal pillar or filler) only bears the load of the immediate roof within the bearing range, rather than the load applied by the movement of the overlying strata within the large structure; at the same time, it seals the tunnel and isolates the goaf, thus effectively preventing dynamic disasters such as rock bursts, etc.