THE STRESS STATE AND FRACTURING OF ROCK MASS OF SARBAY OPEN-CAST MINE

Abstract

To specify the pattern of stress-stain state of rock mass around mine openings of Sarbay iron-ore open-cast mine researches were carried out on principal determination of stress orientation in pristine environment. Gzovsky method was used for solving the assigned task. This method consists of restoration of principal stress axes orientation as the results of rock mass fracturing analysis. According to tectonic physical foundations of the method any tectonic structure is formed due to stress field existing
in Earth's crust which is to be attributed to specified time and place. Five main conjugated fractures were revealed as the result of experimental survey of fracturing on deep levels out-crop of Sarbay pit. Two conjugated fractures that define the direction of principal stresses have sublatitudinal orientation with trend azimuth of 250^o – 290^o and 80^o – 100^o. It was determined, that maximal principal stress is oriented in vertical direction. In-between principal stress is oriented in sublatitudinal direction. Minimal principal stress axis is oriented in submeridional direction, parallel to general cleavage of ore bed. In the paper
an assumption is made that stress distribution in rock mass of deep levels of Sarbay open-cast pit is similar to Dinnik hypothesis. Vertical stress component is determined by overburden weight, and lateral earth pressure coefficient depends on rock mass properties and at average is equal to 0.55.