THE MECHANISM OF UNDERGROUND CAVITIES FORMATION AND THE METHODS OF THEIR ELIMINATION

The article considers the process of cavities formation, as well as both gravity and enforced flow of mortar mixes during their elimination. It is shown that the groutstowing mix is fed from the surface in the opening of critical condition by well, where spreads over its floor and fills the goaf. The process of filling the vacant place with highly dispersive mixtures is considered. Based on the fundamentals of the viscoplastic dissolution flow theory, the process of both gravity and enforced flow of the fluid in the opening is shown. It is proved that the pumping of the grout-stowing mix is a step-bystep process, which ensures the layer-by-layer filling of the opening. It is established that in the case of the gravity flow of the grout mix in the inclined fracture, the mix is displaced by gravity along the incline of the fracture. In addition, it is proved that the dissolution pumping into the vacant place of the opening in the gravity flow regime requires the use of the batching technology. The model describing the hydraulic fluid fluctuation in flooded horizontal cavities, unlimited in terms of area, is proposed. The model is based on the postulate of the constant velocity of the hydraulic fluid fluctuation along the radius and its equality to the critical velocity. It is established that the hydraulic fluid discharge at a constant pressure in the supply pipeline decreases linearly in time.