Method of simulating rock mass stability in laboratory conditions using equivalent materials

Abstract

Purpose. To determine the qualitative composition of the equivalent material of a laboratory model representing Kryvyi Rih iron-ore basin ground, as well as to develop a method to determine its quantitative composition for the study of the rock mass stability in the laboratory conditions with the geometric scale of similarity 1:200. Methods.Laboratory studies on models with geometric scale of similarity 1:200 allowed to establish the dependence of the initial stress changes on the percentage of the components comprising the equivalent material. Findings.As a result, the study found that it is expedient in laboratory conditions to replace the full-size model by the sand and paraffin-based equivalent material consisting of granite chips, cast iron, silica sand, mica and paraffin wax. It was established that the quantitative composition of the equivalent material mixture simulating rocks of Kryvyi Rih iron-ore basin consists of cast iron and granite chips (34%) and silica sand, mica and paraffin (66%).Originality. For the first time, the empirical dependence of initial stress occurring in the equivalent material on the percentage of paraffin and iron has been set. Initial stress in the equivalent material depend directly on the amount of cast iron in the mixture and vary according to the polynomial dependence, and the amount of paraffin in the mixture varies according to the quadratic dependence. Practical implications.The obtained results of laboratory tests can be used with sufficient accuracy for physical modeling of processes occurring in rocks during underground mining, and the resulting values of modeling can be used in the design of stopes to be developed.

Enhancement of the technology of mining steep ore bodies applying the “floating” crown

“…To calculate the safe thickness of a crown, the most reasonable are the methods of structural mechanics that are described in recent scientific works [5,6,[44][45][46]. The authors of the works recommend to distinguish among three types of crowns: а -a long thick beam-like plate constrained along the contour; b -a plate constrained along the contour and with fixed corners if its length-towidth ratio equals or exceeds six; c -a plate constrained along the contour and with fixed corners if its length-towidth ratio is less than six.…”

“…These ore bodies are mined applying surface and underground methods. Underground methods are used to mine rich iron ores with iron content of 57-65% applying stoping systems and bulk caving of ore and overlying rock in proportion of 55% to 45% [5][6][7][8]. Most of underground mines prefer stoping with pillar caving.…”

Safe Development of the Decorative Jaspilites in the Energetically Disturbed Massifs

“…Изучены физические свойства горных пород и новые гипотезы о горном давлении с учетом оценки степени устойчивости обнажений, выявления закономерностей их деформирования и разрушения, увязки извлечения руд и пород во времени и пространстве, определения параметров конструктивных элементов систем разработки, способов крепления и соответствующих типов крепи. Приняты во внимание промышленные, лабораторные и теоретические исследования, проанализированы и обобщены результаты исследований по стандартным и разработанным методикам [2].…”

“…Совокупность техногенных факторов стала причиной неконтролируемого самообрушения массива висячего бока от места ведения добычных работ до земной поверхности, сопровождаемого техногенным горным ударом и локальным землетрясением. Кроме значительных убытков от разрушения вентиляционного ствола, автомобильных дорог и стоянок, а также остановки шахты на 3 мес, катастрофа привела к человеческим жертвам [2].…”

Physical modeling of massif stability when forming and supporting underground workings

“…Порядок проведення лабораторних досліджень та методика вибору складів для моделювання на еквівалентних матеріалах досить повно розглянута в роботах М.І. Ступніка [1,[3][4][5]…”