Physical experiment and numerical simulation of roof failure characteristics in underground mined-out area.

In response to the problem that none-tight contact of filling body and the roof in the underground mined-out area causing roof damage and surface subsidence, this paper uses physical similar simulation and numerical simulation to study the damage deformation law in the roof in the underground mined-out area in terms of damage form and stress, at the same time, the internal displacement of the roof in underground mined-out area is monitored, which reduces the deviation of the influence of single factor and improves the reasonableness of the stability evaluation of the roof of the mined-out area. Through the physical experiment, it is found that under vertical loading, with the increase of load, cracks first appear in the central area of the roof, and gradually develop to the sidewall, until the model is completely destroyed. Through the numerical simulation experiment, it is found that there is a tensile stress concentration area in the central region, which is the most vulnerable to damage. The monitoring results show that with the increase of load, the displacement of the around roof is smaller than that of the central area, the closer to the roof centre, the smaller the displacement difference of the roof. The physical experiment, numerical simulation experiment and monitoring results are compared, and the three are in good agreement. The analysis results have guiding significance for the treatment of underground mined-out areas, underground mining methods and pillar remaining. [ABSTRACT FROM AUTHOR]