The aim of the project. Development of blasting technology for quarries providing safety of near-by constructions.
The state of the art in the field of research. The intensification of mining operations inevitably leads on the one hand to an increase in the mass of explosives during open pit mining, and on the other - to the reduction of the distance between area of mining works and protected structures. As a result, dramatically increases the risk of destruction of various structures (underground mining, administrative and residential buildings, dams, etc.) situated in the immediate vicinity of the venue of mass explosion.
There are several methods for assessing the seismic impact of blasting on the surrounding structures: 1. An analytical method based on Sadovsky formula,
2. An engineering seismometry - this technique is based on the analysis of data recorded by seismometric equipment. Its advantage is that it allows to get "in situ" seismic data, and its disadvantage is the limitation of the data obtained, both in distance and azimuth relative to the shot point, and the incompleteness of the dynamic pattern of seismic action,
3. A numerical simulation by finite element method based on calculation of dynamic impact on the rock massif and secure constructions. This method takes into account big set of the initial data.
Provisional application of numerical analysis has shown the ability to evaluate the seismic effect of mass explosions on protected facilities for different schemes of blasting, as well as to determine the most gentle way of blasting, which provides seismic safet. Thus, this method involving seismometry results for calibration and testing computational models allows to obtain adequate and comprehensive analysis of the seismic effect of mass explosions on protected buildings.
The impact of proposed project on the progress in this field. The method of numerical simulation in heavy mining allows to estimate various blasting options and facilitate making quick decisions. So, it is necessary to create an additional opportunity to receive and process the recorded seismic data, to develop software for estimation and analysis of seismic action and, to implement high-performance computing techniques based on modern hardware-software architectures. Developing and debugging a complex of hardware-software products will provide a significant reduction of the computation time, expand the range of promptly solved tasks and hasten the decision-making.
Such an approach will provide introduction of numerical simulation of explosive seismic impact to projecting and executing drilling and blasting and will allow to develop technological recommendations for maintaining a safe seismic level of quarry blasting.
Expected results and their application. Following results are expected:
· initial digital characteristics of the object of research: a quarry model including: position of secure constructions, a detailed pattern of geomechanical conditions of the rock massif, rock massif geology, the technological parameters of drilling and blasting at quarries (explosives used, initialization tools, delay of drilling technology, etc.);
· assessment of reliability of numerical simulation of explosive seismic impact through a constant refinement, testing and calibration of the calculation model parameters;
· software for calculating and analysing the seismic impact of blasting on secure constructions;
· influence of blasting parameters on the intensity of seismic impact on secure objects during underground drifting;
· recommendations for the technique of blasting in quarries that provides a reduction of the intensity of seismic effect and the risk of seismic hazard.
There will be performed a series of numerical experiments in the course of the project on calculating patterns of velocity, displacement, acceleration and stress in the rock massif, including the vicinity of secure constructions under varying parameters of blasting (delay time, mass of explosive per a delay stage, well pattern, the total mass of explosive, etc.)
The results obtained can be widely used in the future by various mining companies to assess the explosive seismic impact and reduce the risk (probability) of secure object destruction, as well as by technical supervision authorities for clarification or development of new regulations and recommendations ensuring seismic safety during blasting.
