Search results

This research study aims to develop regular cylindrical pore network models (RCPNMs) to calculate topology and geometry properties of explosively created fractures along with their resulting hydraulic permeability. The focus of the investigation is to define a method that generates a valid geometric and topologic representation from a computational modelling point of view for explosion-generated fractures in rocks. In particular, extraction of geometries from experimentally validated Eulerian smoothed particle hydrodynamics (ESPH) approach, to avoid restrictions for image-based computational methods.

Three-dimensional stabilized ESPH solution is required to model explosively created fracture networks, and the accuracy of developed ESPH is qualitatively and quantitatively examined against experimental observations for both peak detonation pressures and crack density estimations. SPH simulation domain is segmented to void and solid spaces using a graphical user interface, and the void space of blasted rocks is represented by a regular lattice of spherical pores connected by cylindrical throats. Results produced by the RCPNMs are compared to three pore network extraction algorithms. Thereby, once the accuracy of RCPNMs is confirmed, the absolute permeability of fracture networks is calculated.

The results obtained with RCPNMs method were compared with three pore network extraction algorithms and computational fluid dynamics method, achieving a more computational efficiency regarding to CPU cost and a better geometry and topology relationship identification, in all the cases studied. Furthermore, a reliable topology data that does not have image-based pore network limitations, and the effect of topological disorder on the computed absolute permeability is minor. However, further research is necessary to improve the interpretation of real pore systems for explosively created fracture networks.

Although only laboratory cylindrical rock specimens were tested in the computational examples, the developed approaches are applicable for field scale and complex pore network grids with arbitrary shapes.

It is often desirable to develop an integrated computational method for hydraulic conductivity of explosively created fracture networks which segmentation of fracture networks is not restricted to X-ray images, particularly when topologic and geometric modellings are the crucial parts. This research study provides insight to the reliable computational methods and pore network extraction algorithm selection processes, as well as defining a practical framework for generating reliable topological and geometrical data in a Eulerian SPH setting.

At the same time, new military and political factors have emerged, which determine the strategy of the Russian defense industry, rates of its development, and change of the structure. On February 8, of the current year, the chief of Pentagon, R. Gates spoke at a session of the Committee for the Armed Forces of the Chamber of Representatives of the Congress, declaring that USA should be ready to possible military conflicts with other countries including Russia and China: “We need the whole spectrum of war facilities for army involving conflicts, since we do not know what could happen in such places as Russia, China, North Korea, Iran and other.”¹ As a result, the USA military policy is encircling Russia with antimissile defense systems. They are supposed to install a powerful radar in the Czech Republic and shaft-basing missiles in Poland. A superpowerful floating radar is to be transferred from Hawaii islands to Aleut islands, etc. Thus, the whole territory of Russia will be surrounded with radar-missile complexes. These activities will produce an increased attention to elaboration and manufacturing of constituents of the antimissile defense system and by-pass systems, possible withdrawal from the Treaty on conventional weapons in Europe and the Treaty on medium-range strategic missiles etc., which may change the direction and paces of development of the defense industry.