The study of stress state and nechanism of rock massif deformation upon the formation of technonatural karst collapses

The paper deals with the assessment of stress-strain state variation in rock massifs upon the formation of displacement moulds and surface sinkholes in the undermined areas of Verkhnekamskoe potassium salt deposit in Perm krai, Russia. Engineering geological conditions, as well as natural and technogenic factors influencing the development of hazardous geological processes are described by the example of one typical site of the deposit. Methodical issues of the development of geomechanical model for this site and compilation of finite-element calculation scheme with selecting calculation parameters of rock properties and boundary conditions of the calculation area are considered. Regularities in the variation of stress fields and rock massif deformations upon cutting mines at one depth are considered. The possible mechanisms of deformation and destruction of karstified rock massifs upon the formation of technonatural sinkholes on the earth surface are described. The results of the study are significant for predicting hazardous processes and undertaking protective measures.