THE MECHANISM OF DESTRUCTION OF FROZEN AND PARTLY MELTED ROCKS ON EXAMPLE OF THE CELICS OF FROSEN COAL
In this work the mechanism of destruction of permafrost on the sample of frozen virgin coal is described. It is considered that the influence of contact conditions of end faces of the pillar with the roof rocks and soil on fracture pattern. Using data from the dynamics of the phase transition boundary, during the melting of the pillar, the mechanism of its destruction is described by stage. We obtained the formula for determining the bearing test of partially thawed coal pillar through the depth of thaw. Analyzing stress condition of partially thawed coal pillar as well as the mechanism of its destruction was developed a formula for determining the bearing capacity of partially thawed coal pillar by the depth of its thawing: the break-down point of frozen coal pillar is reducing due to thawing by linear law with the determining coefficient of which is the percentage of stress softening multiplied by ratio of the average depth of thawing to the width of the pillar. And also the formulas for the definition of optimum size of the interchamber and barrier pillar which are prone to thawing. The practical result of this research is the method developed by author method of evaluation of bearing capacity and choosing the optimum shape of the pillars in frozen virgin coal under thawing effect.