The project aims to develop blasting technology for quarries to reduce the intensity of the seismic effect on secure constructions and associated risks.
There are several methods for assessing the seismic impact of blasting on the surrounding structures: 1) analytical method, which has a drawback of low accuracy since it does not take into account many factors that significantly affect the assessment of seismic action, such as the geologic composition and structure of a massif, physical and mechanical properties of rock, switching of borehole charges, delay value, etc., 2) 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) numerical simulation by finite element method based on calculation of dynamic impact on the rock massif and secure constructions. Numerical modeling method involving the results of seismometry to calibrate and test computational models provides an adequate and comprehensive analysis of the mining explosive seismic impact on secure structures. The possibility of carrying out various numerical experiments allows to determine the parameters of blasting, providing permissible seismic influence on the construction.
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 projection and execution of drilling and blasting and will allow to develop technological recommendations for maintaining a safe seismic level of quarry blasting.
The 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;
· determination of 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.
The project will include a series of numerical experiments 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 by 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.
The primary accomplishment of the project will be analysis of explosive seismic impact on secure constructions by numerical simulations with account for the technology of drilling and blasting at mines. Reliability of the digital model will be provided by continuous testing and calibration of the model parameters using seismic monitoring data.
1- A digital model will be developed using the information about physical and mechanical properties of rock, information about drilling and blasting technology and properties of the explosives used.
2- Stability criteria of secure constructions to seismic action will be determined on the basis of valid maximum permissible parameters of seismic action.
