PREDVIĐANJE SVOJSTAVA HIDRAULIČKOGA RAZBIJAČA STIJENA KOD NJIHOVA ISKAPANJA

The demand for the usage of hydraulic rock breakers in excavating rock masses has increased recently for environmental and economic reasons. The conventional method (i.e., drill and blasting technique) has many restrictions due to environmental aspects. In this paper, we propose a methodology for the prediction of the performance of hydraulic rock breakers in the excavation of a rock mass. The case study area is located in Northwest Egypt on the shoreline of the Mediterranean Sea. Extensive site investigation was implemented using exploration boreholes showing that the majority of the site is limestone with lenses of sands. Based on the collected rock properties, mapping of both the rock quality (RQD) and the uniaxial compressive strength (UCS) for the rock mass was conducted. Such mapping of the mechanical properties helps in the zoning of a rock mass and grouping the similar rock zones of nearly matched properties. Due to economic and machinery availability concerns, this study focuses on very small, small, and medium capacity hydraulic breakers. For each type of rock breaker, calculations of the net breaking rate (NBR) are implemented for each group of the rock with similar properties. The challenge of this methodology is that the excavation of the rock mass shall be implemented in a very limited time frame (only one year ≈ 300 workdays). Therefore, two scenarios of light-duty and medium rock breakers are applied providing the number of machines required with specifications and working days. The first scenario is assigned to medium duty machines, while the second scenario concerns very small to small rock breakers. In general, such a sequence could be adopted for other cases with different rock mass properties, hydraulic breakers specifications and any desired time frame.Potreba uporabe hidrauličkoga razbijača kod pridobivanja stijena postaje sve veća zbog očuvanja okoliša i iz ekonomskih razloga. Konvencionalne metode (poput bušenja i miniranja) imaju mnogo ograničenja s obzirom na njihov utjecaj na okoliš. Ovdje je predložena metodologija kojom se predviđaju svojstva hidrauličkoga razbijača stijena. Kao testno područje odabrano je smjestište u sjeverozapadnome Egiptu, na obali Sredozemnoga mora. Načinjena su brojna istraživanja bušenjem, a rezultati su pokazali kako je u najvećemu dijelu stijenska masa vapnenac s lećama pijeska. Temeljem istraženih svojstava stijena kartirane su kvaliteta stijenske mase i jednoosna tlačna čvrstoća. Rezultati su pomogli u zoniranju stijenske mase i svrstavanju stijena u skupine sličnih svojstava. Zbog ekonomičnosti i dostupnih strojeva istraživanje se odnosilo na razbijače vrlo maloga, maloga i srednjega kapaciteta. Za svaku vrstu izračunan je stvarni iznos lomljenja u pojedinačnim skupinama stijena. Pri tomu je izazov predstavljao vremenski ograničeno iskopavanje/lomljenje koje se obavljalo tijekom 1 godine, tj. 300 radnih dana. Razrađena su dva scenarija, prvi za strojeve srednjega i drugi za one maloga kapaciteta s potrebnim brojem jedinica i radnih dana za svaki. Prikazani algoritam može se primijeniti za druge slučajeve, s različitim svojstvima stijena, strojeva i vremenskoga okvira

Rock Mass Fracture Detection and Modelling Using GPR for Evaluation and Production Optimization of Ornamental Stone Deposits

The thesis presents new solutions for the fractures problem in ornamental stone quarries which entails economic and material loses. The thesis aimed at developing methodologies and providing solutions for evaluation and production optimization of ornamental stone deposits. Ground Penetrating Radar (GPR) was selected, among several methods, as a fracture detection tool for this research. A combination of the use of a low frequency GPR antenna and laboratory rock tests for evaluation of an ornamental stone deposit showed encouraging results. Based on GPR survey, particularly high frequency antennas, a 3D deterministic fracture modeling approach was developed and implemented in several case studies of block and bench scales. A fracture index was proposed for deposit evaluation based on fracture detections from GPR survey. Additionally, an in-situ GPR test allowed formulating a propagation velocity model for 3D mapping of the dielectric constant of the medium, within macro and micro scale of the rock mass of a bench in a sandstone quarry. This finding is significant for future improvement of the deterministic accuracy level of the developed fracture modeling approach and, generally, for the GPR applications in rock mass. Regarding quarrying optimization, two 3D algorithms, based on fracture modeling or mapping, were developed for production and/or revenue optimization of cutting slabs from blocks and cutting blocks from benches. The algorithms were coded in two software packages named SlabCutOpt and BlockCutOpt. SlabCutOpt was applied to a case study of a limestone block through testing 37 different commercial-sizes of slabs, investigating the optimization results in terms of recovery ratio (a geo-environmental direction) and revenue (an economic direction). BlockCutOpt was applied to two case studies (quarries) with different site characteristics. The results showed that optimum cutting direction of blocks can vertically and horizontally vary, giving geometric information about the cutting grid of blocks that optimizes the production

A Combination of GPR Survey and Laboratory Rock Tests for Evaluating an Ornamental Stone Deposit in a Quarry Bench

Abstract The paper examines methods of assessing the critical fractures and quality of an ornamental stone deposit. Fracture status was evaluated by an in-situ Ground Penetrating Radar (GPR) test. The resulting 3D GPR model allowed exploration of the extension, shape, and orientation of the detected fractures surfaces. It also identified a rock stratum with a noticeably lower load of critical fractures compared to the other strata. Physico-mechanical properties were investigated by laboratory tests allowing classification of the deposit into quality categories, which provided a promising correlation with the GPR survey results

Macro-Scale Underground Geomechanical and Thermal Mapping for Very Shallow Geothermal Applications

The document is an extended abstract presented at "GeoENV 2016", the 11th International Conference on Geostatistics for Environmental Application Conference, 6-8 July 2016, Lisbon, Portugal

Experimental calibration of underground heat transfer models under a winery building in a rural area

Ground temperature and hydrogeological conditions are key parameters for many engineering applications, such as the design of building basements and underground spaces and the assessment of shallow geothermal energy potential. Especially in urban areas, in the very shallow depths, it is diffi cult to fi nd natural undisturbed underground thermal conditions because of anthropic interventions. The assessment of underground behaviour in disturbed conditions will become more and more relevant because of increasing awareness to energy effi ciency and renewable energy topics. The purpose of this paper is to show a three-dimensional representation - based on models calibrated on experimental data - of the underground thermal behaviour aff ected by a building in a rural area in Italy. Temperature varies in space and time and it depends on ground, climate and building characteristics, and all these parameters are taken into account by the seasonal periodic modelling implemented. The results obtained in a context of low urbanization indirectly suggest the importance of these eff ects in dense urban areas; taking greater account of these aspects could lead to improvements in the design of underground spaces and geo-exchanger fi elds for geothermal energy exploitation

Effect of adding growth factors during in vitro maturation on the developmental potentials of ewe oocytes selected by brilliant cresyl blue staining

Aim: Several factors had been concerned with the developmental competence of the sheep oocyte. This study aims to investigate the effect of adding growth factors (insulin-like growth factor 1 [IGF-1] and epidermal growth factor [EGF]) in the maturation medium of ewe oocytes selected based on brilliant cresyl blue (BCB) screening on in vitro maturation (IVM), fertilization, and pre-implantation embryo development. Materials and Methods: Cumulus-oocyte complexes (COCs) were obtained from the ovaries of slaughtered ewes by either aspiration or slicing techniques. COCs were in vitro matured in a medium containing IGF-1 and EGF (control group). For BCB screening, oocytes were stained and divided into BCB+ oocytes that matured in the same maturation conditions without adding growth factors (Group 2) or in the presence of growth factors (Group 3), and BCB– oocytes that matured in medium without growth factors (Group 4) or with growth factors (Group 5). Results: The supplementation of the maturation medium with growth factors during IVM of (BCB+) oocytes resulted in a significant increase in nuclear maturation rate (90.9%), fertilization rate (75.6%), and embryo developmental rates (60.0%, 46.7%, and 33.3% for cleavage, morula, and blastocyst, respectively). Conclusion: Culturing BCB+ oocytes in a maturation medium containing both EGF and IGF-1 showed a significant improvement in nuclear maturation, fertilization, and pre-implantation embryo development in vitro

Damage Evolution of Granodiorite after Heating and Cooling Treatments

The awareness of the impact of high temperatures on rock properties is essential to the design of deep geotechnical applications. The purpose of this research is to assess the influence of heating and cooling treatments on the physical and mechanical properties of Egyptian granodiorite as a degrading factor. The samples were heated to various temperatures (200, 400, 600, and 800 °C) and then cooled at different rates, either slowly cooled in the oven and air or quickly cooled in water. The porosity, water absorption, P-wave velocity, tensile strength, failure mode, and associated microstructural alterations due to thermal effect have been studied. The study revealed that the granodiorite has a slight drop in tensile strength, up to 400 °C, for slow cooling routes and that most of the physical attributes are comparable to natural rock. Despite this, granodiorite thermal deterioration is substantially higher for quick cooling than for slow cooling. Between 400:600 °C is ‘the transitional stage’, where the physical and mechanical characteristics degraded exponentially for all cooling pathways. Independent of the cooling method, the granodiorite showed a ductile failure mode associated with reduced peak tensile strengths. Additionally, the microstructure altered from predominantly intergranular cracking to more trans-granular cracking at 600 °C. The integrity of the granodiorite structure was compromised at 800 °C, the physical parameters deteriorated, and the rock tensile strength was negligible. In this research, the temperatures of 400, 600, and 800 °C were remarked to be typical of three divergent phases of granodiorite mechanical and physical properties evolution. Furthermore, 400 °C could be considered as the threshold limit for Egyptian granodiorite physical and mechanical properties for typical thermal underground applications

Three dimensional fractures detection by geo-radar for sustainable production of ornamental stones

Fractures in rock mass threaten exploitability and productivity of ornamental stones quarries. Since propagation of fractures inside the rock mass is a random phenomenon, a non-destructive detection method of fractures shall be used. Between several fractures detection methods, Ground Penetrating Radar (GPR) was selected as data acquisition tool. GPR is fast, accurate and reliable method of fractures detection in rock masses. The in-situ survey, in a case study in a sandstone quarry in Firenzuola, Italy, was planned for achieving two main targets. The first one was focused on accurately modeling fractures as 3D surfaces from data obtained by a high frequency GPR antenna. The second main target was focused on surveying the rock mass to detect large aperture fractures surfaces as deep as possible by a low frequency GPR antenna. The proposed method was applied to two different benches using 400 MHz and 70 MHz antennas. A visualized 3D semi-deterministic model (as close as possible to reality) of sub-horizontal and sub-vertical fractures in a rock mass of 25 m length x 6m width x 2.5m depth was obtained from the high frequency GPR antenna survey. Whilst the low GPR frequency antenna survey allowed characterizing the extension, shape and orientation of the detected fractures surfaces in a rock mass of 12m length x 7m width x 14m depth. Moving from these results to further sustainable objectives, suggested exploitation and planning scenarios based on the presented fracture models are described in this paper in objectives to short term production optimization and long term production planning

Законодательная техника в условиях инновационного развития общества

The exploitation potential of shallow geothermal energy is usually defined in terms of site-specific ground thermal characteristics. While true, this assumption limits the complexity of the analysis, since feasibility studies involve many other components that must be taken into account when calculating the effective market viability of a geothermal technology or the economic value of a shallow geothermal project. In addition, the results of a feasibility study are not simply the sum of the various factors since some components may be conflicting while others will be of a qualitative nature only. Different approaches are therefore needed to evaluate the suitability of an area for shallow geothermal installation. This paper introduces a new GIS platform-based multicriteria decision analysis method aimed at comparing as many different shallow geothermal relevant factors as possible. Using the Analytic Hierarchic Process Tool, a geolocalized Suitability Index was obtained for a specific technological case: the integrated technologies developed within the GEOTeCH Project. A suitability map for the technologies in question was drawn up for Europe

Suitability Evaluation of Specific Shallow Geothermal Technologies Using a GIS-Based Multi Criteria Decision Analysis Implementing the Analytic Hierarchic Process

The exploitation potential of shallow geothermal energy is usually defined in terms of site-specific ground thermal characteristics. While true, this assumption limits the complexity of the analysis, since feasibility studies involve many other components that must be taken into account when calculating the effective market viability of a geothermal technology or the economic value of a shallow geothermal project. In addition, the results of a feasibility study are not simply the sum of the various factors since some components may be conflicting while others will be of a qualitative nature only. Different approaches are therefore needed to evaluate the suitability of an area for shallow geothermal installation. This paper introduces a new GIS platform-based multicriteria decision analysis method aimed at comparing as many different shallow geothermal relevant factors as possible. Using the Analytic Hierarchic Process Tool, a geolocalized Suitability Index was obtained for a specific technological case: the integrated technologies developed within the GEOTeCH Project. A suitability map for the technologies in question was drawn up for Europe