Studying the deformation and failure of salt rocks for geomechanical assessing the stability of elements of the system for the mining at potash deposits

Abstract

Сomplex studies aimed at developing methods for assessing the stability of inter-chamber pillars used in the conditions of the Verkhnekamskoe potash salt deposit has been carried out. Field measurements of massif deformations in the vicinity of the treatment chambers were done using contour and deep reference points. It has been established that the most informative indicator reflecting the geomechanical situation in the underground section of the potassium salt deposit is the lateral deformation of the pillars.

To assess the standard rates of deformation of inter-chamber pillars, laboratory research was conducted to study the deformation of salt samples under the action of a constant load in the step loading mode, as well as the determination of longitudinal and lateral deformations during compression of large scale samples.

As a part of the development of a method for calculating the equivalent strength of inter-chamber pillars, complex experimental studies were undertaken on layered cement-sand samples.

In order to reveal the influence of the length of inter-chamber pillars on their stability, experimental studies of the shape coefficient were held on rectangular sylvinite samples of various lengths.

To take into account the influence of the time factor on the stability and deformability of the rocks in the roof of mine workings, the creep of salt rocks under uniaxial stepped tension was studied experimentally.

Within the framework of solving the problem of transferring the results of experimental determination of physical and mechanical properties of rocks to the full-scale level, theoretical and experimental studies were conducted to detect the scale effect in salt rocks under uniaxial compression.