In the given paper the authors present the results of investigation of rock masses natural stressed state in complex conditions. These results are based on the numerous measurements of stress parameters in natural conditions directly. As a result of the data analysis mentioned above the authors have set up a hypothesis concerning formation mechanism of rock masses modern stressed state.
The present state of the industry development is characterized by growing difficulties of technogenic (engineering) interaction of the man with lithosphere (rock masses). This is especially displayed in the spheres of civil engineering and mining. In the latter case these difficulties are more significant which is mainly caused by mining of mineral resources situated in the rocks with complex mining- engineering and hydrogeological conditions at large depths including. In the complex of these conditions natural (in nature) stressed state of the rocks themselves is one of the most important ones. The problem of natural rock masses stressed state has more than an age-long history which can be divided into two stages. During the first stage natural stressed state of rock masses and Earth's crust (lithosphere) in general was considered as the result of rock masses weight action (gravitational forces) Rock masses stressed state character was considered as geostatic (Jacoby O.,A.N. Dinnik) and as hydrostatic (Game A., Talobr M.). The secon (present) stage is characterized by the following: rock masses stressed state is considered as geodynamic caused by joint action of gravitational forces and tectonic processes occuring in the Earth's geological history at present (Chast, Vatsnauer, Turchaninov, Gzovsky). Revision of the knowledge about rock masses stressed state was based on geological structures analysis (natural resources deposits and construction sites of power generating stations), analysis of the Earth's crust shifts measurement results, the results analysis of natural studies (measurements) of rock masses stressed state and ore (rock) pillars at mineral resources deposits. The results of numerous investigations analysis in nature of natural stress fields of rock masses of complex geological structure show that they are characterized by considerable irregularity, stress value, their direction (orientation) and distribution in rock masses. On the strength of this we can consider that natural stressed state on concrete areas of Earth's crust and even of separate areas of rock masses is connected with geological processes history and present-day shifts (force fields) at these areas. In connection with this it is necessary to underline that variety of structures supposes variety of natural stresses fields in these structures. This causes great difficulties in establishing objective laws not only in qualitative aspect as well. Besides it is difficult to solve control problems of stressed- deformed state of mining-engineering structures constructive elements while mining, constructing and expliotation of some engineering structures situated in the rock masses. Hence, solution of one of the main problems of mining (and underground construction) - rock-masses control problem is intensified. Undoubtedly this arises the necessity of experimental study of natural stresses fields parameters in concrete mining-geological conditions.
