Search results for: rock and water combination

Authors: Clarence Dissanayake, Anishka A. Hettiarachchi

Abstract:

Landscape architecture needs to encompass a placemaking process carefully composing and manipulating landscape elements to address perceptual needs of humans, especially aesthetic, psychological and spiritual. The objective of this qualitative investigation is to inquire the impact of elements of rock and water combination on landscape perception and related feelings, emotions, and behavior. The past empirical studies have assessed the impact of landscape elements in isolation on user preference, yet the combined effect of elements have been less considered. This research was conducted with reference to the verity of qualities of water and rock through a visual landscape quality assessment focusing on landscape qualities derived from five visual concepts (coherence, historicity imageability, naturalness, and ephemera). 'Kaludiya Pokuna' archeological site in Anuradhapura was investigated with a sample of University students (n=19, male 14, female 5, age 20-25) using a five-point Likert scale via a perception based questionnaire and a visitor employed photographic survey (VEP). Two hypothetical questions were taken into investigation concerning biophilic (naturalness) and topophilic (historicity) aspects of humans to prefer a landscape with rock and water. The findings revealed that this combination encourages both biophilic and topophilic aspects, but in varying degrees. The identified hierarchy of visual concepts based on visitor’s preference signify coherence (93%), historicity (89%), imageability (79%), naturalness (75%) and ephemera (70%) respectively. It was further revealed that this combination creates a scenery more coherent dominating information processing aspect of humans to perceive a landscape over the biophilic and topophilic aspects. Different characteristics and secondary landscape effects generated by rock and water combination were found to affect in transforming a space into a place, full filling the aesthetic and spiritual aspects of the visitors. These findings enhance a means of making places for people, resource management and historical landscape conservation. Equalization of gender based participation, taking diverse cases and increasing the sample size with more analytical photographic analysis are recommended to enhance the quality of further research.

Keywords: landscape perception, visitor’s preference, rock and water combination, visual concepts

Procedia PDF Downloads 191

Authors: Junlong Shang, Zhengxian Chua, Hoongping Peh, Zhiye Zhao

Abstract:

Due to scarce land resources in Singapore, it is imperative to increase water storage capacities to meet the increasing demand of water to secure a sustainable development, which can be achieved in the underground by rock caverns. In this paper, a preliminary study on the effects of cavern span, height and radius on the cavern stability is presented to provide a guidance on the cavern construction in the context of Singapore. It is found that the radius of caverns should be around half of the span width (i.e., B/R=2) to reduce vertical displacement at the crown of cavern. The smaller the rock cover, the smaller displacement. The minimum rock thickness should be at least the same as the cavern span to eliminate excessive yielded element. Finally, rock support system is introduced to maintain the profile of caverns.

Keywords: cavern dimension, numerical modelling, sustainable development, underground rock cavern

Procedia PDF Downloads 290

Authors: Peña A. Roland R., Lozano P. Jean P.

Abstract:

The waterflooding process is an enhanced oil recovery (EOR) method that appears tremendously successful. This paper shows the importance of the role of the numerical modelling of waterflooding and how to provide a better description of the fluid flow during this process. The mathematical model is based on the mass conservation equations for the oil and water phases. Rock compressibility and capillary pressure equations are coupled to the mathematical model. For discretizing and linearizing the partial differential equations, we used the Finite Volume technique and the Newton-Raphson method, respectively. The results of three scenarios for waterflooding in porous media are shown. The first scenario was estimating the water saturation in the media without rock compressibility and without capillary pressure. The second scenario was estimating the front of the water considering the rock compressibility and capillary pressure. The third case is to compare different fronts of water saturation for three fluids viscosity ratios without and with rock compressibility and without and with capillary pressure. Results of the simulation indicate that the rock compressibility and the capillary pressure produce changes in the pressure profile and saturation profile during the displacement of the oil for the water.

Keywords: capillary pressure, numerical simulation, rock compressibility, two-phase flow

Procedia PDF Downloads 91

Authors: H. Vahdani

Abstract:

By the adsorption of polar compounds and/or the deposition of organic material, the wettability of originally water-wet reservoir rock can be altered. The degree of alteration is determined by the interaction of the oil constituents, the mineral surface, and the brine chemistry. Recently improving oil recovery by tuning wettability alteration is believed as a new recovery method. Various researchers have demonstrated that low salt water injection has a significant impact on oil recovery. It has been shown, for instance, that additional oil can be produced from reservoir rock by managing the injection water. Large wettability sensitivity has been observed, indicating that the oil/water capillary pressure profiles play a major role during low saline water injection simulation. Although the exact physics on how this alteration occurs is still a research topic; however, it has been reported that some of its effect can be captured by a relative permeability shift from an oil-wet system to a water-wet system. Modeling of low salt water injection mainly is based on the theory of wettability alteration and is hence strongly dependent on the wettability of the reservoir. In this article, combination of different wettabilities has been simulated and it is observed that the highest recoveries were from the cases were the reservoir initially was water-wet, and the lowest recoveries was from the cases were the reservoir initially was considered oil-wet. However for the cases where the reservoir initially was oil-wet, the effect of low-salinity waterflooding was the largest.

Keywords: low salt water injection, wettability alteration, modelling, relative permeability

Procedia PDF Downloads 461

Authors: Muhammad Tarmidzi, Reza M. G. Gani, Andri Luthfi

Abstract:

The purpose of this study is to identify rock zone containing hydrocarbons with calculating rock property includes volume shale, total porosity, effective porosity and water saturation. Identification method rock property based on GR log, resistivity log, neutron log and density rock. Zoning is based on sequence stratigraphic markers that are sequence boundary (SB), transgressive surface (TS) and flooding surface (FS) which correlating ten well log in blok “M”. The results of sequence stratigraphic correlation consist of eight zone that are two LST zone, three TST zone and three HST zone. The result of rock property calculation in each zone is showing two LST zone containing hydrocarbons. LST-1 zone has average volume shale (Vsh) 25%, average total porosity (PHIT) 14%, average effective porosity (PHIE) 11% and average water saturation 0,83. LST-2 zone has average volume shale (Vsh) 19%, average total porosity (PHIT) 21%, average effective porosity (PHIE) 17% and average water saturation 0,82.

Keywords: hydrocarbons zone, petrophysic, rock property, sequence stratigraphic

Procedia PDF Downloads 277

Authors: Ibrahim Abdel Gadir Malik, Dafalla Siddig Dafalla, Osama Abdelgadir El-Bushra

Abstract:

Geological and engineering characteristics of intact rock and the discontinuity surfaces was used to describe and classify rock mass into zones based on mechanical and physical properties. Many conditions terms that affect the rock mas; such as Rock strength, Rock Quality Designation (RQD) value, joint spacing, and condition of joint, water condition with block size, joint roughness, separation, joint hardness, friction angle and weathering were used to classify the rock mass into: Good quality (class II) (RMR values range between 75% and 56%), Good to fair quality (class II to III) (RMR values range between 70% and 55%), Fair quality (class III) (RMR values range between 60% and 50%) and Fair to poor quality (Class III to IV) (RMR values, range between (50% and 35%).

Keywords: rock strength, RQD, joints, weathering

Procedia PDF Downloads 377

Authors: Rahman Abdullayev

Abstract:

Rituals took place during the rock art production or in the rock art sites can be found reflection in contemporary culture. But the form of rituals was conducted in association with rock art production still uncertain. The main purpose of this research is to define the form of ritual activities that took place in the rock art sites, by the example of Bronze Age rock art of Gobustan. For ritual activity location of the rocks which were selected for making petroglyphs has important significance. Thus, not all the rocks which were suitable for rock art were used for this purpose. If in Upper Paleolithic, Mesolithic, Neolithic periods Gobustan inhabitants executed petroglyphs on the wall of rock shelters, but in Bronze Age they made it on rocks which are in front of the large, open spaces. A recent study of the location of Bronze Age rock art of Gobustan and involving ethnographic information to the interpretation of drawings allows defining the form of rituals which took place in Gobustan at Bronze Age.

Keywords: Bronze Age, Gobustan, ritual, rock art

Procedia PDF Downloads 198

Authors: Mojtaba Heydarizad

Abstract:

Khorasan Razavi is the second most important province in north-east of Iran, which faces a water shortage crisis due to recent droughts and huge water consummation. Kardeh and Torogh dam reservoirs in this province provide a notable part of Mashhad metropolitan (with more than 4.5 million inhabitants) potable water needs. Hydrochemical analyses on these dam reservoirs samples demonstrate that MgHCO₃ in Kardeh and CaHCO₃ and to lower extent MgHCO₃ water types in Torogh dam reservoir are dominant. On the other hand, Gibbs binary diagram demonstrates that rock weathering is the main factor controlling water quality in dam reservoirs. Plotting dam reservoir samples on Mg²⁺/Na⁺ and HCO₃^-/Na⁺ vs. Ca²⁺/ Na⁺ diagrams demonstrate evaporative and carbonate mineral dissolution is the dominant rock weathering ion sources in these dam reservoirs. Cluster Analyses (CA) also demonstrate intense role of rock weathering mainly (carbonate and evaporative minerals dissolution) in water quality of these dam reservoirs. Studying water quality by the U.S. National Sanitation Foundation (NSF) WQI index NSF-WQI, Oregon Water Quality Index (OWQI) and Canadian Water Quality Index DWQI index show moderate and good quality.

Keywords: hydrochemistry, water quality classification, water quality indexes, Torogh and Kardeh dam reservoir

Procedia PDF Downloads 223

Authors: Ahmed T. Farid, Muhammed Rizwan

Abstract:

Geotechnical study for evaluating soil or rock permeability is a highly important parameter. Permeability values for rock formations are more difficult for determination than soil formation as it is an effect of the rock quality and its fracture values. In this research, the prediction of in situ permeability of limestone rock formations was predicted. The limestone rock permeability was evaluated using Lugeon tests (in-situ packer permeability). Different sites which spread all over the Riyadh region of Saudi Arabia were chosen to conduct our study of predicting the in-situ permeability of limestone rock. Correlations were deducted between the values of in-situ permeability of the limestone rock with the value of the rock quality designation (RQD) calculated during the execution of the boreholes of the study areas. The study was performed for different ranges of RQD values measured during drilling of the sites boreholes. The developed correlations are recommended for the onsite determination of the in-situ permeability of limestone rock only. For the other sedimentary formations of rock, more studies are needed for predicting the actual correlations related to each type.

Keywords: In situ, packer, permeability, rock, quality

Procedia PDF Downloads 347

Authors: Dhara Adhnandya Kumara, Novrizal Novrizal

Abstract:

Hot Dry Rock (HDR) is one of geothermal energy which is abundant in many provinces in Indonesia. Heat exploitation from HDR would need a method which injects fluid to subsurface to crack the rock and sweep the heat. Water is commonly used as the working fluid but known to be less effective in some ways. The new research found out that Supercritical CO2 (SCCO2) can be used to replace water as the working fluid. By studying heat transfer efficiency, pumping power, and characteristics of the returning fluid, we might decide how effective SCCO2 to replace water as working fluid. The method used to study those parameters quantitatively could be obtained from pre-existing researches which observe the returning fluids from the same reservoir with same pumping power. The result shows that SCCO2 works better than water. For cold and hot SCCO2 has lower density difference than water, this results in higher buoyancy in the system that allows the fluid to circulate with lower pumping power. Besides, lower viscosity of SCCO2 impacts in higher flow rate in circulation. The interaction between SCCO2 and minerals in reservoir could induce dehydration of the minerals and enhancement of rock porosity and permeability. While the dissolution and transportation of minerals by SCCO2 are unlikely to occur because of the nature of SCCO2 as poor solvent, and this will reduce the mineral scaling in the system. Under those conditions, using SCCO2 as working fluid for HDR extraction would give great advantages to advance geothermal energy in Indonesia.

Keywords: geothermal, supercritical CO2, injection fluid, hot dry rock

Procedia PDF Downloads 195

Authors: M. Mazraehli, F. Mehrabani, S. Zare

Abstract:

In general, mechanical and hydraulic processes are not independent of each other in jointed rock masses. Therefore, the study on hydro-mechanical coupling of geomaterials should be a center of attention in rock mechanics. Rocks in their nature contain discontinuities whose presence extremely influences mechanical and hydraulic characteristics of the medium. Assuming this effect, experimental investigations on intact rock cannot help to identify jointed rock mass behavior. Hence, numerical methods are being used for this purpose. In this paper, water inflow into a tunnel under significant water table has been estimated using hydro-mechanical discrete element method (HM-DEM). Besides, effects of geomechanical and geometrical parameters including constitutive model, friction angle, joint spacing, dip of joint sets, and stress factor on the estimated inflow rate have been studied. Results demonstrate that inflow rates are not identical for different constitutive models. Also, inflow rate reduces with increased spacing and stress factor.

Keywords: distinct element method, fluid flow, hydro-mechanical coupling, jointed rock mass, underground excavations

Procedia PDF Downloads 134

Authors: Sahand Golmohammadi, Sana Hosseini Shirazi

Abstract:

Because the status and mechanical parameters of discontinuities in the rock mass are included in the calculations, various methods of rock engineering classification are often used as a starting point for the design of different types of structures. The Q-system is one of the most frequently used methods for stability analysis and determination of support systems of underground structures in rock, including tunnel. In this method, six main parameters of the rock mass, namely, the rock quality designation (RQD), joint set number (Jn), joint roughness number (Jr), joint alteration number (Ja), joint water parameter (Jw) and stress reduction factor (SRF) are required. In this regard, in order to achieve a reasonable and optimal design, identifying the effective parameters for the stability of the mentioned structures is one of the most important goals and the most necessary actions in rock engineering. Therefore, it is necessary to study the relationships between the parameters of a system and how they interact with each other and, ultimately, the whole system. In this research, it has attempted to determine the most effective parameters (key parameters) from the six parameters of rock mass in the Q-system using the rock engineering system (RES) method to improve the relationships between the parameters in the calculation of the Q value. The RES system is, in fact, a method by which one can determine the degree of cause and effect of a system's parameters by making an interaction matrix. In this research, the geomechanical data collected from the water conveyor tunnel of Azad Dam were used to make the interaction matrix of the Q-system. For this purpose, instead of using the conventional methods that are always accompanied by defects such as uncertainty, the Q-system interaction matrix is coded using a technique that is actually a statistical analysis of the data and determining the correlation coefficient between them. So, the effect of each parameter on the system is evaluated with greater certainty. The results of this study show that the formed interaction matrix provides a reasonable estimate of the effective parameters in the Q-system. Among the six parameters of the Q-system, the SRF and Jr parameters have the maximum and minimum impact on the system, respectively, and also the RQD and Jw parameters have the maximum and minimum impact on the system, respectively. Therefore, by developing this method, we can obtain a more accurate relation to the rock mass classification by weighting the required parameters in the Q-system.

Keywords: Q-system, rock engineering system, statistical analysis, rock mass, tunnel

Procedia PDF Downloads 37

Authors: Mohammad Mohammadi, Mojtaba Askari, Mohammad Farouq Hossaini

Abstract:

An intrinsic property of rock mass known as rock bolt supporting factor (RSF) or rock bolting capability of rock mass was developed and used for explanation of the mechanism of rock bolting practice. Based on the theory of RSF, numeral values can be assigned to each given rock mass to show the capability of that rock mass to be reinforced by rock bolting. For determination of shotcrete thickness, both safety and cost must be taken into account. The present paper introduces a scientific approach for determination of the necessary shotcrete thickness in underground structures for support purposes using the concept of rock bolt supporting factor (RSF). The proposed approach makes the outcome of shotcrete design one step more accurate than before. The actual dataset of 500 meters of Alborz Tunnel length is used as an example of the application of the approach.

Keywords: rock bolt supporting factor (RSF), shotcrete design, underground excavation, Alborz Tunnel

Procedia PDF Downloads 282

Authors: Samia Ait Ali Yahia

Abstract:

In Algeria, the most impressive and most known prehistoric art is the painted or engraved rock art which is present with abundance in several regions. The existence of rock art in Great Kabylia region has been known for over sixty years. The main purpose of this research is to show the dangers facing these rock paintings and engravings and what are the arrangements for their protection and recovery. As every vestige destroyed is a part of the world's memory which disappears, some steps have to be taken in order to protect these historical and archaeological heritages.

Keywords: rock paintings and engravings, preservation, valorization, Kabylia

Procedia PDF Downloads 426

Authors: B. L. Avanthi Isaka, P. G. Ranjith

Abstract:

The development of technically-sound enhanced geothermal systems (EGSs) is identified as a viable solution for world growing energy demand with immense potential, low carbon dioxide emission and importantly, as an environmentally friendly option for renewable energy production. The use of supercritical carbon dioxide (ScCO₂) as the working fluid in EGSs by replacing traditional water-based method is promising due to multiple advantages prevail in ScCO₂-injection for underground reservoir stimulation. The evolution of reservoir stimulation using ScCO₂ and the understanding of the flow behavior of a ScCO₂-stimulated geothermal reservoir is vital in applying ScCO₂-EGSs as a replacement for water-based EGSs. The study is therefore aimed to investigate the flow behavior of a ScCO₂-fractured rock medium at in-situ stress and temperature conditions. A series of permeability tests were conducted for ScCO₂ fractured Harcourt granite rock specimens at 90ºC, under varying confining pressures from 5–60 MPa using the high-pressure and high-temperature tri-axial set up which can simulate deep geological conditions. The permeability of the ScCO₂-fractured rock specimens was compared with that of water-fractured rock specimens. The results show that the permeability of the ScCO₂-fractured rock specimens is one order higher than that of water-fractured rock specimens and the permeability exhibits a non-linear reduction with increasing confining pressure due to the stress-induced fracture closure. Further, the enhanced permeability of the ScCO₂-induced fracture with multiple secondary branches was explained by exploring the CT images of the rock specimens. However, a single plain fracture was induced under water-based fracturing.

Keywords: supercritical carbon dioxide, fracture permeability, granite, enhanced geothermal systems

Procedia PDF Downloads 108

Authors: Md. Kamal Uddin, Abdul Shukor Juraimi, Md. Parvez Anwar

Abstract:

Seawater with reduced herbicide could be considered as a low cost environment friendly alternative method for weed control in turfgrass. Different concentration of sea water in combination with trifloxysulfuron-sodium and quinclorac were used to determine weed control level in turfgrass field. The weed species S. diander, C. aromaticus, and C. rotundus except E. atrovirens were fully controlled when treated with ¾ recommended trifloxysulfuron–sodium with sea water, ¾ recommended trifloxysulfuron–sodium with ¾ sea water, ½ recommended trifloxysulfuron–sodium with sea water, ¾ recommended quinclorac with sea water and ¾ recommended quinclorac with ¾ sea water. Eragrostis atrovirens showed maximum 48% injury when treated with ¾ recommended trifloxysulfuron–sodium and sea water. Among the tested turf grasses, P. vaginatum showed only 8% injury to sea water in combination with ¾ recommended quinclorac, indicating greater salt tolerance. Zoysia japonica also showed no more than 14% injury when treated with sea water in combination with ¾ recommended trifloxysulfuron–sodium or quinclorac.

Keywords: sea water, trifloxysulfuron–sodium, quinclorac, turf

Procedia PDF Downloads 346

Authors: Shahin Shabani, Pouya Pourmadadi

Abstract:

Tunnel boring machines (TBMs) have been used for the construction of various tunnels for mining projects for the purpose of access, conveyance of ore and waste, drainage, exploration, water supply and water diversion. Several mining projects have seen the successful and economic beneficial use of TBMs, and there is an increasing awareness of the benefits of TBMs for mining projects. Key technical considerations for the use of TBMs for the construction of tunnels for mining projects include geological issues (rock type, rock alteration, rock strength, rock abrasivity, durability, ground water inflows), depth of cover and the potential for overstressing/rockbursts, site access and terrain, portal locations, TBM constraints, minimum tunnel size, tunnel support requirements, contractor and labor experience, and project schedule demands. This study focuses on tunnelling mining, with the goal to develop methods and tools to be used to gain understanding of these processes, and to analyze metro of Tehran. The Metro Line 7 of Tehran is one of the Longest (26 Km) and deepest (27m) of projects that’s under implementation. Because of major differences like passing under all geotechnical layers of the town and encountering part of it with underground water table and also using mechanized excavation system, is one of special metro projects.

Keywords: TBM, tunnel boring machines economic, metro, line 7

Procedia PDF Downloads 345

Authors: Natália Botica, Luís Luís, Paulo Bernardes

Abstract:

The Côa Valley, listed World Heritage since 1998, presents more than 1300 open-air engraved rock panels. The Archaeological Park of the Côa Valley recorded the rock art motifs, testing various techniques based on direct tracing processes on the rock, using natural and artificial lighting. In this work, integrated in the "Open Access Rock Art Repository" (RARAA) project, we present the methodology adopted for the vectorial drawing of the rock art motifs based on orthophotos taken from the photogrammetric survey and 3D models of the rocks. We also present the information system designed to integrate the vector drawing and the characterization data of the motifs, as well as the open access sharing, in order to promote their reuse in multiple areas. The 3D models themselves constitute a very detailed record, ensuring the digital preservation of the rock and iconography. Thus, even if a rock or motif disappears, it can continue to be studied and even recreated.

Keywords: rock art, archaeology, iron age, 3D models

Procedia PDF Downloads 55

Authors: Ayedun Hassan, Ayadi Odunayo Peter

Abstract:

The ancient city of Abeokuta has been supplied with pipe borne water since 1911, yet, a continuous increase in population and unplanned city expansion makes water a very precious and scarce commodity. The government reserved areas (GRA’s) are well planned, and public water supply is available; however, the sub-urban areas consist of scattered structures with individuals trying to source water by digging wells and boreholes. The geology of the city consists of basement rock which makes digging wells and boreholes very difficult. The present study was conducted to assess the risk arising from the consumption of toxic elements in the groundwater of Abeokuta, Ogun State, Nigeria. Forty-five groundwater samples were collected from nine different areas of Abeokuta and analyzed for physicochemical parameters and toxic elements. The physicochemical parameters were determined using standard methods, while the toxic elements were determined using Inductively Coupled Plasma-Mass Spectrometer (ICP/MS). Ninety-six percent (96%) of the water sample has pH < 6.5, and 11% has conductivity > 250 µSCm⁻¹ limits in drinking water as recommended by WHO. Seven percent (7%) of the samples have Pb concentration >10 µgL⁻¹ while 75% have Al concentration >200 µgL⁻¹ recommended by WHO. The order for risk of cancer from different area of Abeokuta are Cd²⁺ > As³⁺ > Pb²⁺ > Cr⁶⁺ for Funaab, Camp and Obantoko; As³⁺ > Cd²⁺ > Pb²⁺ > Cr⁶⁺ for Ita Osin, Isale Igbein, Ake and Itoku; Cd²⁺ >As > Cr⁶⁺ > Pb²⁺ for Totoro; Pb²⁺ > Cd²⁺ > As³⁺ > Cr⁶⁺ for Idiaba. The order of non-cancer hazard index (HI) calculated for groundwater of Abeokuta City are Cd²⁺ > As³⁺ > Mn²⁺ > Pb²⁺ > Ni²⁺ and were all greater than one, which implies susceptibility to other illnesses. The sources of these elements are the rock and inappropriate waste disposal method, which leached the elements into the groundwater. A combination of sources from food will accumulate these elements in the human body system. Treatment to remove Al and Pb is necessary, while the method of water distribution should be reviewed to ensure access to potable water by the residents.

Keywords: Abeokuta, groundwater, Nigeria, risk

Procedia PDF Downloads 60

Authors: S. A. Agbalajobi, W. A. Bello

Abstract:

This study examines rock properties of crushed aggregate in some selected quarries in Kwara state, Nigeria. Some physical properties (chemical composition, mineral composition, particle size distribution) of gneiss sample were determined using ISRM standards. The physicomechanical properties (specific gravity, dry density, porosity, water absorption, point load index, tensile, and compressive strength) of the gneiss rock were evaluated. The analysis on the gneiss samples revealed the mean dry density and the unit weight are 2.52 g/m3, 2.63 g/m3, 2.38 g/m3; and 24.1 kN/m3, 25.78 kN/m3, 23.33 kN/m3, respectively (for locations A,B,C). The water absorption level of the gneiss rock sample ranged from 0.38 % – 0.57 % for the three locations. The mean Schmidt hammer rebound value ranged from 51.0 – 52.4 for the three locations and mean point load index values ranged from 9.89 – 10.56 MPa classified as very high strength while the uniaxial compressive strength of the rock samples revealed that its strength ranged from 120 - 139 MPa (for location A, B, and C) classified as strong rock. The aggregate impact value test and aggregate crushing value test conducted on the gneiss aggregates from the three locations in accordance with British Standard. The gneiss sample from the three locations (A, B, and C) is a good material for the production of construction works such as concrete, bricks, pavement, embankment among others, the compressive strength of the material is within the accepted limit.

Keywords: gneiss, aggregate impact, aggregate crushing, physic-mechanical properties, rock hardness

Procedia PDF Downloads 273

Authors: Li Hung-Hui, Chen Chi-Chieh, Yang Zon-Yee

Abstract:

This study aims to explore the impact energy absorption in the fragmented processes of rock samples during the split-Hopkinson-pressure-bar tests. Three kinds of rock samples including granite, marble and sandstone were tested. The impact energy absorptions were calculated according to the incident, reflected and transmitted strain wave histories measured by a oscilloscope. The degree of fragment rocks after tests was quantified by the box dimension of the fractal theory. The box dimension of rock fragments was obtained from the particle size distribution curve by the sieve analysis. The results can be concluded that: (1) the degree of rock fragments after tests can be well described by the value of box dimension; (2) with the impact energy absorption increasing, the degrees of rock fragments are varied from the very large fragments to very small fragments, and the corresponding box dimension varies from 2.9 to 1.2.

Keywords: SHPB test, energy absorption, rock fragments, impact loading, box dimension

Procedia PDF Downloads 419

Authors: Claudia H. Swanson, Jens Günster

Abstract:

This research addresses the densification via compaction and sintering of naturally occurring rock salt which was motivated by the fact that in a saline environment rock salt is thermodynamically stable and does show a mechanical behavior compatible to the surrounding host material. The sintering of rock salt powder compacts was systematically investigated using temperature and pressure as variables for the sinter process. The behavior of rock salt showed segregations of anhydrite, CaSO4 - the major impurity found in rock salt, to the grain boundaries between individual sodium chloride crystals. Powder compacts treated with lower pressures lost those anhydrite segregates over time while high pressure treated compacts remained with anhydrite segregates. The density reached in this study is 2.008 g cm-3 corresponding to a density of 92.5 % of the theoretical value. This high density is making the sintering a promising technique for rock salt as applications in underground appropriate environment.

Keywords: rock salt, sinter, anhydrite, nuclear safety

Procedia PDF Downloads 467

Authors: Hadi Farhadian, Homayoon Katibeh

Abstract:

Groundwater inflow to the tunnels is one of the most important problems in tunneling operation. The objective of this study is the investigation of model dimension effects on tunnel inflow assessment in discontinuous rock masses using numerical modeling. In the numerical simulation, the model dimension has an important role in prediction of water inflow rate. When the model dimension is very small, due to low distance to the tunnel border, the model boundary conditions affect the estimated amount of groundwater flow into the tunnel and results show a very high inflow to tunnel. Hence, in this study, the two-dimensional universal distinct element code (UDEC) used and the impact of different model parameters, such as tunnel radius, joint spacing, horizontal and vertical model domain extent has been evaluated. Results show that the model domain extent is a function of the most significant parameters, which are tunnel radius and joint spacing.

Keywords: water inflow, tunnel, discontinues rock, numerical simulation

Procedia PDF Downloads 495

Authors: Hyung T. Kwak, Jun Gao, Yao An, Alfred Kleinhammes, Yue Wu

Abstract:

Surface wettability is a crucial factor in oil recovery. In oil industry, the rock wettability involves the interplay between water, oil, and solid surface. Therefore, studying the interplay between adsorptions of water and hydrocarbon molecules on solid surface would be very informative for understanding rock wettability. Here we use the in-situ Nuclear Magnetic Resonance (NMR) gas isotherm technique to study competitive adsorptions of water and isopropanol, an intermediate step from hydrocarbons. This in-situ NMR technique obtains information on thermodynamic properties such as the isotherm, molecular dynamics via spin relaxation measurements, and adsorption kinetics such as how fast the system can reach thermal equilibrium after changes of vapor pressures. Using surfaces of silica glass beads, which can be modified from hydrophilic to hydrophobic, we obtained information on the influence of surface hydrophilicity on the state of surface water via obtained thermodynamic and dynamic properties.

Keywords: Wettability, NMR, Gas Isotherm, Hydrophilicity, adsorption

Procedia PDF Downloads 155

Authors: Gökhan Altay, Cafer Kayadelen

Abstract:

Rock fall is a movement of huge rock blocks from dip slopes due to physical effects. It generally occurs where loose tuffs lying under basalt flow or stringcourse is being constituted by limestone layers which stand on clay. By corrosion of some parts, big cracks occur on layers and these cracks continue to grow with the effect of freezing-thawing. In this way, the breaking rocks fall down from these dip slopes. Earthquakes which can induce lots of rock movements is another reason for rock fall events. In Turkey, we have a large number of regions prone to the earthquake as in the World so this increases the possibility of rock fall events. A great number of rock fall events take place in Turkey as in the World every year. The rock fall events occurring in urban areas cause serious damages in houses, roads and workplaces. Sometimes it also hinders transportation and furthermore it maybe kills people. In Turkey, rock fall events happen mostly in Spring and Winter because of freezing- thawing of water in rock cracks frequently. In mountain and inclined areas, rock fall is risky for engineering construction and environment. Some countries can invest significant money for these risky areas. For instance, in Switzerland, approximately 6.7 million dollars is spent annually for a distance of 4 km, to the systems to prevent rock fall events. In Turkey, we have lots of urban areas and engineering structure that have the rock fall risk. The embankments are preferable for rock fall events because of its low maintenance and repair costs. Also, embankments are able to absorb much more energy according to other protection systems. The current design method of embankments is only depended on field tests results so there are inadequate studies about this design method. In this paper, the field test modeled in three dimensions and analysis are carried out with the help of ANSYS programme. By the help of field test from literature the numerical model validated. After the validity of numerical models additional parametric studies performed. Changes in deformation of embankments are investigated by the changes in, geometry, velocity and impact height of falling rocks.

Keywords: ANSYS, embankment, impact height, numerical analysis, rock fall

Procedia PDF Downloads 480

Authors: Jian-Xiu Wan, Yao Yin

Abstract:

In complex terrain and poor geological conditions areas, Railway, highway and other transportation constructions are still strongly developing. However, various geological disasters happened such as landslide, rock heap and so on. According to the results of geological investigation, the form of skirt (trapezoidal), semicircle and triangle rock heaps are mainly due to complex internal force and external force, in a certain extent, which is related to the terrain, the nature of the rock mass, the supply area and the surface shape of rock heap. Combined with the above factors, discrete element numerical simulation of rock mass is established under different terrain conditions based on 3DEC, and accelerated formation process of rock heap under seismic action is simulated. The fragmentation structure supply area is calculated, in which the most dangerous area is located. At the same time, the formation mechanism and development process are studied in different terrain conditions, and the structure of rock heap is judged by section, which can provide a strong theoretical and technical support for the prevention and control of geological disasters.

Keywords: 3DEC, fragmentation structure, rock heap, slope, seismic action

Procedia PDF Downloads 273

Authors: Aybike Ayfer Karadağ

Abstract:

Today, the amount of water available is decreasing day by day due to global warming, environmental problems and population increase. To protect water resources, it is necessary to take a lot of measures from the global scale to the local scale. Some of these measures are related to spatial planning studies. In this study, the impact of water process analysis was assessed in the development of spatial planning for water conservation. The study was conducted in the Kovada sub-watershed (Isparta, Turkey). By means of water process analysis, the way to reach underground water of surface water in the study area is mapped. In this context, plant cover, soil and rock permeability were evaluated holistically with geographic information systems technologies. Then, on the map, water permeability is classified and this is spatially expressed. The findings show that the permeability of the water is different in the study case. As a result, the water permeability map needs to be included in the planning for water conservation planning.

Keywords: water, conservation, spatial planning, water process analysis

Procedia PDF Downloads 181

Authors: Intisar, Khalifa, Salim, Al Busaidi

Abstract:

Recently, the synergic combination of low salinity water flooding with polymer flooding has been a subject of paramount interest for the oil industry. Numerous studies have investigated the efficiency of enhanced oil recovery using low salinity polymer flooding (LSPF). However, there is no clear conclusion that can explain the incremental oil recovery, determine the main factors controlling the oil recovery process, and define the relative contribution of rock/fluids or fluid/fluid interactions to extra oil recovery. Therefore, this study aims to perform a systematic investigation of the interactions between oil, polymer, low salinity and sandstone rock surface from pore to core scale during LSPF. Partially hydrolyzed polyacrylamide (HPAM) polymer, Boise outcrop, a crude oil sample and reservoir cores from an Omani oil field, and brine at two different salinities were used in the study. Several experimental measurements including static bulk measurements of polymer solutions prepared with brines of high and low salinities, single phase displacement experiments, along with rheological, total organic carbon and ion chromatography measurements to analyze ion exchange reactions, polymer adsorption, and viscosity loss were used. In addition, two-phase experiments were performed to demonstrate the oil recovery efficiency of LSPF. The results revealed that the incremental oil recovery from LSPF was attributed to the combination of the reduction in the water-oil mobility ratio, an increase in the repulsion forces between crude oil/brine/rock interfaces and an increase in pH of the aqueous solution. In addition, lowering the salinity of the make-up brine resulted in a larger conformation (expansion) of the polymer molecules, which in turn resulted in less adsorption and a greater in-situ viscosity without any negative impact on injectivity. This plays a positive role in the oil displacement process. Moreover, the loss of viscosity in the effluent of polymer solutions was lower in low-salinity than in high-salinity brine, indicating that an increase in cations concentration (mainly driven by Ca2+ ions) has stronger effect on the viscosity of high-salinity polymer solution compared with low-salinity polymer.

Keywords: polymer, heavy oil, low salinity, COBR interactions

Procedia PDF Downloads 54

Authors: Abhishek Ranka

Abstract:

Rock-cut Architecture is a manifestation of human endurance in constructing magnificent structures by sculpting and cutting entire hills. Cave Architecture in India form an important part of rock-cut development and is among the most prolific examples of rock-cut architecture in the world. There are more than 1500 rock-cut caves in various regions of India. Among them mostly are located in western India, more particularly in the state of Maharashtra. Some of the rock-cut caves are located in the central region of India, which is presently known as Malawa (Madhya Pradesh). The region is dominated by the vidhyachal hill ranges toward the west, dotted with the coarse laterite rock. Dhamnar Caves have been excavated in the central region of Mandsaur Dist. With a combination of shared sacred faiths. The earliest rock-cut activity began in the north, in Bihar, where caves were excavated in the Barabar and the Nagarjuni hills during the Mauryan period (3rd century BCE). The rock-cut activity then shifts to the central part of India in Madhya Pradesh, where the caves at Dhamnar, Bagh, Udayagiri, Poldungar, etc. excavated between 3rdto 9ᵗʰ CE. The rock-cut excavation continued to flourish in Madhya Pradesh till 10ᵗʰ century CE, simultaneously with monolithic Hindu temples. Dhamnar caves fall into four architectural typologies: the Lena caves, Chaitya caves, Viharas & Lena-Chaityagriha caves. The Buddhist rock-cutting activity in central India is divisible into two phases. In the first phase (2ndBCE-3rd CE), the Buddha image is conspicuously absent. After a lapse of about three centuries, activity begins again, and the Buddha images this time are carved. The former group belongs to the Hinayana (Lesser Vehicle) phase and the latter to the Mahayana (Greater Vehicle). Dhamnar caves has an elaborate facades, pillar capitals, and many more creative sculptures in various postures. These caves were excavated against the background of invigorating trade activities and varied socio-religious or Socio Cultural contexts. These caves also highlights the wealthy and varied patronage provided by the dynasties of the past. This paper speaks about the appraisal of the rock cut mechanisms, design strategies, and approaches while promoting a scope for further research in conservation practices. Rock-cut sites, with their physical setting and various functional spaces as a sustainable habitat for centuries, has a heritage footprint with a researchquotient.

Keywords: rock-cut architecture, buddhism, hinduism, Iconography, and architectural typologies, Jainism

Procedia PDF Downloads 112

Authors: Samia Ait Ali Yahia

Abstract:

The rock paintings of Grande Kabylia contain a good number of Libyan inscriptions. Of the 54 sites discovered, 23 have inscriptions painted in red ocher. We find them in rock shelters, on blocks of sandstone in the northern part of Kabylia. Our job is to collect as many cave paintings as possible with Libyan inscriptions. Then we will make an analysis on the epigraphic level, the different forms of the characters and their frequencies. The other purpose of this research is to bring out the different characters used in these paintings and compare them with those of the Libyan steles of Grande Kabylia.

Keywords: Grande Kabylia, Libyan inscriptions, Libyan stele, rock paintings

Procedia PDF Downloads 106