Investigation of the Geomechanical Situation in the Rock Mass in the Zone of Influence of Cleaning Operations in the Conditions of the Khromtau Mine Field

Abstract

Goal. The forecast of the stress-strain state (VAT) in the rock mass in the zone of influence of cleaning operations when using the self-destruction development system and the calculation of the bearing capacity of the supports of the mine workings used at the Khromtau mine. Methodology. The complex of geological and engineering data on the properties of the host rocks is analyzed. Numerical modeling of the stress-strain state of the rock mass and calculation of the bearing capacity of the types of supports used at the mine in the RS2 program, which works on the basis of the Finite Element Method in a two-dimensional formulation, which allowed us to take into account a significant number of factors affecting the state of the array. The HoekBrown model was used as a model of array behavior, the distinctive advantage of which is its nonlinearity. Results. The values of the main stresses and the load on the support are obtained. According to the results of numerical analysis of the stress-strain state of the rock mass at a depth of 900 m (horizon – 480 m), the dominant stresses are close to hydrostatic σ1 = σ3 = σz = 24.8 MPa. A predictive assessment of the stability reserve of mine workings before and after the cleaning work has been carried out, according to the results of which it should be assumed that the stability reserve of the workings passed in the cleaning area is below the minimum allowable, therefore, collapses and an increase in the load on the support are possible. The reference pressure on the support of the workings at a depth of 900 m (-480 m) is calculated. Calculation of the parameters of the support for workings laid at a horizon of 480 m was carried out.. Scientific novelty. The nature and features of the regularities of the formation of the stress-strain state within the boundaries of the influence of various variants of cleaning operations of block 20-28 on the horizon of 480 m are established and a quantitative assessment of the values of loads on the support of the pumping orts of the workings of the horizon is given. Practical significance. The results of the research can be applied to the creation of a geomechanical model of the deposit and the design of stable parameters of the support of mine workings