In the development of ore deposits and stratum-shaped thick deposits in most cases are used chamber systems with multi-stage ore excavation, resulting in the formation of unconfined cavities of significant volumes ...

At present, considerable experience of experimental and theoretical studies on stress distribution around excavations of different cross-sectional shape has been accumulated. Most of these studies have been carried out in relation to workings with a smooth contour, however, it is known that the drilling and blasting method of sinking produces an uneven contour of the excavation. Technological irregularities formed in this process, and also occurring in some cases rock dumps, cause redistribution of stresses with the formation of zones of increased concentration. In full-scale conditions it is difficult to determine the value of stress concentration in these zones. Therefore, studies are usually carried out on models.

The stability of the rock massif in a group of mine workings depends to a great extent on their mutual location and the ratio of cross-sectional dimensions, as well as on the nature of the application of loads. Below we consider the results of the study of the stressed state of rocks during two vertical workings at the Tekeli mine, where the shaft with a diameter of 6.7 m and the ore spout with a diameter of 3.4 m were passed at a distance between their axes of 15 m to the depth of X horizon (572 m). In unstable rocks the mutual influence of these workings on each other leads to significant deformations of rocks and their dumps.

When developing powerful steeply falling formations with the division of the floor into sub-floors (for example, at hydro-mines), effective means of supporting the sub-floor drifts are required. The support should provide reliable stability of drifts and ease of its installation - conditions for high rates of drifting by shearers or hydro-monitors. The type of such support depends primarily on the amount of rock pressure, which is the result of the distribution of stresses in the rock mass around the excavation.

Optical method of stress modeling is now widely used in the study of stress distribution in various building structures, in solving problems of hydraulic engineering, theoretical mechanics and is becoming more and more widespread in mining. The most important issue in this research method is the quality of the material of models, as its properties determine the possibilities of the method and the technique of the experiment. The application of the polarization-optical method to the study of rock pressure issues is particularly difficult because elastic properties are not equally inherent in all rocks. In a number of cases, rocks reveal properties of plasticity, anisotropy, have fractured or layered structure.

A large amount of work in the construction of mines, as is known, falls on mining operations, and the greatest complexity and labor intensity is the conduct of vertical shafts. In recent years, many new machines, mechanisms and different types of equipment have been created, which allowed to significantly increase the rate of mining excavations, in particular vertical shafts. So, according to D. I. Maliovanov, in the coal industry with an increase in the volume of sinking vertical shafts from 5958 meters in 1946 to 20 724 meters in 1956. The level of mechanization of rock loading increased from 2.3% in 1948 to 87.4% in 1956. Maximum rates of vertical shaft sinking increased from 69.4 m in 1946 to 202.1 m in 1955, 241.1 m in 1957 and 264.6 m in 1959.