DOWNHOLE METHOD FOR DETERMINATION OF DIRECTION AND MAIN STRESS VALUES Russian patent published in 2016 - IPC E21C39/00 

FIELD: mining.

SUBSTANCE: invention relates to mining and can be used for determining the direction of action and values of primary stresses in rock mass, evaluation of stress-strain state of mine rock massif, detection of location zones of rock damage and nature of their propagation in underground mining of mineral deposits. Method involves drilling of wells or boreholes in underground mine workings with length from 5 m, with diameter from 40 mm. On internal surface of wells marks are applied in the form of circle with marker or paint. Position of the video endoscope camera relative to horizon is determined, direction of deformation of horizontal and inclined wells, shifts and orientation of cracks are determined with video endoscope in examined wells. Obtained images efficiently determine minimum diameter of the well, the direction of which corresponds to the direction of maximum stresses in rock massif. At the specified parameters are determined images circuits d₁, d₂, the direction of maximum compression well indicates the direction of action of maximum stresses σ_1. Following values are determined: angle α between the vertical and the direction of maximum stresses, angle β between image vertical and the direction of action of maximum stresses, thrust slip ΔH.Graphic image of the analyzed sections is plotted with tracing of, for example, site deformation or slip scheme. Well deformation is determined depending on d₁ - initial well diameter, d₂ - minimum diameter of the well under deformation and K₁ - empirical coefficient taking into account physical and mechanical properties of rocks and structural forest renewal changing massif in direction of maximum stress.

EFFECT: technical result consists in improvement of accuracy of determination of the direction of main stresses, enhancing security and efficiency of field development.

1 cl, 3 dwg