DBPapers
DOI: 10.5593/sgem2017/22/S09.034

ENSURING THE SAFETY OF UNDERGROUND OPERATIONS BY COMBINING METHODS FOR ESTIMATING THE DISPLACEMENTS PARAMETERS

D. A. Ilyukhin, D. Kh. Rakhatkulov
Wednesday 13 September 2017 by Libadmin2017

References: 17th International Multidisciplinary Scientific GeoConference SGEM 2017, www.sgem.org, SGEM2017 Conference Proceedings, ISBN 978-619-7408-02-7 / ISSN 1314-2704, 29 June - 5 July, 2017, Vol. 17, Issue 22, 273-280 pp, DOI: 10.5593/sgem2017/22/S09.034

ABSTRACT

When conducting underground works, it is necessary to take into account their possible consequences for underground and surface objects. The purpose of this work was to identify the need to use three basic methods for estimating and predicting the parameters of subsidence of the earth’s surface and deep layers. The process of extracting minerals from the earth’s interior leads to an increasing need for underground excavations beneath the area of protected objects (surface and underground). In this regard, engineers require more accurate and reliable methods for predicting the possible impact of excavations. Existing methods are usually divided in three groups: mathematical calculations, field observations analysis, and modern finite elements modelling[1]. The first group is based on the experience of underground mining and in fact involves the study of a multitude of excavation objects in terms of the process of shifting. The results of the investigation of these processes are applied to the studied object under the condition of geological similarity. The obvious disadvantage of this method is extremely low reliability without the use of additional measures. At the same time, the method is used quite often because of very low costs, especially in case of low requirements to the accuracy of the excavation impact prediction. The second group involves the use of so-called surface and underground observation stations to monitor the current shifts of the earth’s surface and the excavation horizon. Permanent deformation monitoring is performed based on the monitoring data, enabling timely security measures. This method is the most reliable and costliest because of the large amount of work. The latter group implies the use of very expensive and sophisticated software complexes modelling the state of rock mass. The conducted researches have shown that the effectiveness of the considered methods can be repeatedly increased with their simultaneous application on one object. In this case, the reference method is the observation station, because as a result of monitoring the mine surveyor receives real data on the displacements. Case studies have shown that the reliability of mathematical calculations is significantly increased when there is the possibility of comparing the results with field data on the dynamics of the displacement process[1,3]. In addition, the availability of data from the observation station reduces the impact of deficiencies in finite element modelling complexes[3,5]. Their main disadvantage is the low correspondence of the model to real conditions, especially in cases of complex geological structure of the object[5]. With the use of observation station data it is possible to calibrate the model, which will significantly increase the accuracy of calculations and, together with other methods, will improve the safety of underground excavations.

Keywords: monitoring, observation station, displacements, undermining, deformations, finite elements