Prediction of hydrogeomechanical processes in undermining of water bodies

Rivers, arable land, engineering structures, urban buildings, and communications often fall into the zone of influence of mining operations. Insufficiently justified mining development often leads to negative environmental and social consequences of the violation or destruction of these objects. On the other hand, surface and underground waters often complicate the development of minerals, negatively affecting the safety of production. The paper deals with the interaction of hydrogeological and geomechanical processes near water bodies in complex mining and hydrogeological conditions. One field of research is based on the development of an engineering approach to the analysis of the interaction of hydrogeological and deformation processes. In this case, the results of instrumental field observations and experience of mining operations near water bodies are used. In this approach, it is assumed that six zones can be distinguished in the under-worked rock mass: collapsed rock; through cracks; partially through cracks; individual cracks that do not form a single system; the zone without discontinuities of continuity; the zone of high stresses and compression deformations. As an example of the application of this approach, the development of a mineral deposit under a river is considered and recommendations are made for the preservation of the earth’s surface from waterlogging. The second field of research is related to mathematical modeling and the use of crack theory. The results of the simulation showed that a spontaneous hydraulic fracturing crack may develop in the underworked rock mass, which can serve as a main channel for the penetration of underground or surface water into the mine workings. The nature of spontaneous hydraulic fracturing of rocks is determined by the fact that when a man-made impact on the rock mass, one of the main stresses of the rock mass can become less than the hydrostatic pressure of water. In this case, a hydraulic fracturing crack develops in the area where this condition is met. As an example, the breakthrough of water from a surface reservoir into an underground mine is considered. It is shown that at a low crack resistance of rocks, it is possible for a crack to grow into the mine, which may result in a sudden water breakthrough. The acquired knowledge expands the scientific basis for the development of appropriate supplements to the instructions for mining operations under water bodies.