Transleited: Miteyko Vitaly S.

Determine the laws for pressure, from the walls of the trace AVAILABLE distance bolts deep ROCK MASS

UDC 622,281
Assoc., Ph.D. Sakhno IG, MA Shuliak YA.O., MA Miteyko VS Donetsk National Technical University, Donetsk, Ukraine.

With increasing depth of mining is deteriorating geological conditions, it promotes a more intensive education and growth around the excavation damage zone rocks (DRP) and, accordingly, increase the intensity of their displacement in the cavity output.

To preserve the stability of rocks within the SORP proposed a method based on raspor destroyed rocks with self-expanding compositions [1]. The maining parameter of the proposed method of ensuring the stability of workings is the distance between the hole with a spacing components. Laboratory investigations of domestic self-expanding properties of the material NRW-80 [2,3] allow to determine the pressure developed self-expanding composition, with different coefficients loosening rocks.

The determine of the zone of influence of one element of the spacer, seeks to study the laws governing the transfer of pressure from the walls of the hole containing the distance bolts deep rock mass In this article.

This task was carried out finite element method using the software ANSYS. The problem was solved in the bulk formulation, because of the axisymmetric problem simulated half-section along the vertical axis of the hole. The modeling was made in 1:1 scale. Baseline data for modeling were taken from the inventory of the physical properties of rocks to the conditions of Donetsk-Makeyevsky coal-bearing area. Simulated trace with a spacer element located in the siltstone and the strength of uniaxial compression-35MPa. The inner surface of the simulated hole was applied distributed load corresponding to the pressure from somorasshireniya NRW-80.

This analysis of the patterns of stress distribution leads to the conclusion that the area of influence of the hole is quite limited. In addition a province rocks around the hole to a depth equal to the diameter of the hole will be destroyed from the compressive stresses.

To determine the effective influence of the hole with a spacer element were constructed curves of the change of equivalent von Mises stress on Qekv MPa with increasing distance from the walls of the hole at a distance a, m.

Defining the necessary pressure on the border zones of influence adjacent boreholes, such as 5% of the pressure on the walls of the hole, using the graphs shown in Figure 3, we can establish the distance between the hole for the simulated rock. The specified distance is 0,4 m and 0,6 m in solving the problem of an elastic ruler and a nonlinear formulation, respectively. In our view the task in a nonlinear formulation is closer to reality, especially given the fact of the destruction of okoloshpurovoy of rocks.

Processing simulation results allowed to obtain graphs characterizing the variation of the transfer of pressure through the rock mass Fig.4. Figure 4 on abscissa is the ratio of the distance from the central axis of the hole to the radius of the hole R2 R1, the vertical axis is the ratio of the pressure P2 occurring at a distance of R2 to the pressure P1 exerted on the walls of the hole NRW.

Analysis of the graphs suggests that the coefficient of transmission of pressure is reduced depending on close to exponential.

Thus, our studies suggest that the rate of load transfer from the spacer element is located in the deep borehole carefully rock mass decreases exponentially with increasing distance from the central axis of the hole. This zone is effectively influencing the hole located in the siltstone and the strength to uniaxial compression 30MPa and characteristics for the Donetsk-Makeyevsky district is 0,4-0,6 m

References

1. Сахно И.Г., Петренко Ю.А., Овчаренко Н.А. Лабораторные исследования особенностей работы разрушенных горных пород при формировании из них несущей конструкции/ Проблеми гірського тиску 2008р., №16-с. 70-81.

2. Касьян Н.Н., Овчаренко Н.А., Сахно И.Г., Петренко Ю.А., Самусь О.Л. Лабораторные исследования работы невзрывчатых разрушающих веществ при упрочнении массивов разрушенных горных пород// Науковій вісник НГУ. 2008р.-№8-с. 50-52.

3. Касьян Н.Н., Сахно И.Г. Лабораторные исследования влияния компонентного состава НРВ-80 на его рабочую характеристику при укреплении вмещающего горные выработки массива// Вісник Криворізького технічного університету. 2009р.-№23-с.31-34