If you need assistance with writing your essay, our professional essay writing service is here to help! Important aspects of the procedure include measuring the vertical load in the lower half of the box, and maintaining the size of the opening between the two halves of the shear box at a fixed value of approximately 10-20 times the mean particle diameter of the test specimen. Geological setting From geological point of view the study area is located in an alluvium plain which some sedimentary rocks have outcrops as small hills. Retrouvez Groundwater Reserve Assessment: Application of Electrical Resistivity Method et des millions de livres en stock sur Amazon.fr. The landslides are often triggered by water accumulation within part of the slope which leads to weakening of a section of the slope. The normal stresses and the corresponding values of ?f obtained from a number of strength parameters are determined. Free resources to assist you with your university studies! The ground resistivity is related to various geological parameters such as the mineral and fluid content, porosity and degree of water saturation in the rock. The relationship between the “apparent” resistivity and the “true” resistivity is a complex relationship. Electric surveys are used instead of drilling methods to eliminate the chance of … Variations in electrical resistivity may indicate change in composition,layer thickness, or contaminant levels. resistivity method @Termium Traductions devinées. Thus, it is important to accurately map the zone of ground water accumulation. From a practical perspective, the direct shear test has many advantages for examining interface behavior, including the ability to simulate different loading paths (Boulon 1989, Boulon et al. The resistivity procedure begins in the 1920’s due to the research of the Schlumberger brothers. Electrical resistivity method was adopted in mapping sand/gravel beds for commercial mining and delineation of water table in Njaba river bank and environs. Several standard electrode arrays are available, with different horizontal and vertical resolution, penetration depth and signal-to-noise ratio. The remainder of the device was assembled and the initial thickness of the soil specimen were determined from the vertical dial, which has been previously calibrated under the normal load with the blank substituted for specimen. In this method, the centre point of the electrode array remains unchanged, but the spacing between the electrodes is increased to produce more explaination about the deeper sections of the subsurface. However, at the present time, Dahlin (1996) reported that 2-D surveys are the most effective economic acceptance between obtaining very successful results and keeping the survey expenses down. The important point for a designer concerned with stability analysis is that the shearing resistance in a sample or direct shear test on a sample deposited vertically in the apparatus develops along the bedding planes in the soil,and this corresponds closely with the minimum plane strain shearing resistance in the soil, Tatsuoka et al (1986). Achetez neuf ou d'occasion In this article we will discuss about the applications of low and high resistivity materials in electrical engineering. The direct shear box apparatus is simple to use and has a long history in soil mechanics. By continuing you agree to the use of cookies. The porosity of this soil is low and its moisture content and saturation percentage is high. From simple essay plans, through to full dissertations, you can guarantee we have a service perfectly matched to your needs. The bad economic effects of landslides include the cost to repair structures, loss of property value, distruption of lost timber and fish stocks. 2. The resistivity is useful for detecting lateral and vertical changes in subsurface electrical properties on the same time. Water is one of the essential necessities of nature, indispensible to all organic life and a necessary resource for livelihood; so therefore, its importance cannot be overemphasized. n'importe quels mots . (http://www.marimari.com/hotel/malaysia/hill/fraser.html). afficher. Direct shear are repeated on similar samples at various normal stresses. Electrical resistivity imaging (ERI) known also as electrical resistivity tomography (ERT) or continuous vertical electrical sounding (CVES), described in detail by Dahlin (1996) and Loke (2011), has been used in the investigations. Faire correspondre . In recent years complex ERT inversion techniques have been constructed, making tomographic imaging of subsurface ?uid movement possible. Applicable alternative technique in groundwater exploration such as ERM which complement with existing conventional method may produce comprehensive and convincing output thus effective in terms of cost, time, data coverage and sustainable. (2007), and one of the most important landslide sites is located in the Altindag district. This is not an example of the work produced by our Essay Writing Service. Potts, Dounias and Vaughan (1987) performed a finite element analysis and concluded that the non-uniformities within the direct shear box sample have little affect on the stress-strain behavior, and with little error the test may be interpreted as if it were a simple shear test. The calculated resistivity value is not the true resistivity of the subsurface, but an “apparent” value which is the resistivity of a homogeneous ground which will give the same resistance value for the same electrode arrangement. Electrical resistivity imaging is a widely used tool in near surface geophysical surveys for investigation of various geological, environmental and engineering problems including landslide. Copper: It is most widely used metal because soft its high conductivity (i.e., low resistivity), Silver has the lowest resistivity but due to its high cost it is not used as conducting material. In this section, we will look at the steps involved in converting the apparent resistivity values into a resistivity model section will be discussed. One landslide occurred in km 90,FT055,Kuala Lumpur/Kuala Lipis (Gap Road/Tranum),Fraser Hill starting December 16 2007 until almost recently. In tropical countries where yearly rainfall can reach as high as 4500mm and high temperatures around the year caused extreme weathering to their soil and rock profile where in certain area can stretch out 100 m in depth. Study for free with our range of university lectures! The free program, RES2DMOD.EXE, is a 2-D forward modeling program which calculates the apparent resistivity pseudosection for a user defined 2-D subsurface model. Because of global climate change, drought occurs in increasing intensity and frequency across the world. Exemples Décliner. The loading paths possible with direct shear interface testing bracket those expected along a pile interface, i.e., lying somewhere between a constant normal stress and constant volume condition. For example, with waste detection, electric resistivity techniques may provide a more environmentally friendly way of acquiring data. It utilizes direct currents or low frequency alternating currents to investigate the electrical properties (resistivity) of the subsurface. The computer program RES2DINV.EXE will automatically subdivide the subsurface into a number of blocks, and it then uses a least-squares inversion scheme to determine the appropriate resistivity value for each block. Landslide occurrence is common in hilly terrain of the tropical region due to weather conditions, thick soil profile and lack of slope stability analysis. The evaporation process with the movement of the evaporation front in the studied soil sample was also discussed in depth. Resistivity meters normally give a resistance value, R = V/I, so in practice the apparent resistivity value is calculated by. This method has greater signal-to-noise ratio than the dipole-dipole method because the potential electrodes are placed between the two current electrodes. Figure 3: Data Acquisition Map of the Study Area. To export a reference to this article please select a referencing stye below: If you are the original writer of this essay and no longer wish to have your work published on UKEssays.com then please: Our academic writing and marking services can help you! The direct shear test has been criticized for the non-homogeneity of the stress-strain state within the direct shear box; however, numerical modeling using the finite element method has demonstrated close similarity between the direct shear and the simple shear test (Jewell 1989). The electrical resistivity method is the most widely used and it has proved particularly effective in groundwater exploration because many geological formation properties such as porosity and permeability that are critical to hydrogeology can be correlated with electrical conductivity signatures (Eke and Igboekwe, 2011). Electrical Resistivity Method (ERM) is … From these measurements, the true resistivity of the subsurface can be estimated. Boulon (1989) and Boulon et al. Afficher les traductions générées par algorithme. A range of behaviors can be investigated by applying these test conditions to soils with different initial states ranging from very loose to very dense. The spatial and temporal variations of soil water content during evaporation process can be well characterized by ERM. You can view samples of our professional work here. Anonymous 2005. The ERT studies were performed along four profiles over the landslide body in the directions of N-S and E-W. A Wenner-Schlumberger configuration was used during the resistivity measurements. Jan Mudler, Andreas Hördt, Anita Przyklenk, Gianluca Fiandaca, Pradip Kumar Maurya, Christian Hauck, Two-dimensional inversion of wideband spectral data from the capacitively coupled resistivity method – first applications in periglacial environments, The Cryosphere, 10.5194/tc … A change in electrical resistivity may suggest changes in composition, layer thickness, or pollution levels. An environmental chamber filled with initially saturated sand was designed for the evaporation test. According to Srinivasamoorthy (2009), the important purpose of electrical surveys is to determine the subsurface resistivity distribution by making measurements on the ground surface. *You can also browse our support articles here >. Electrical resistivity imaging is a widely used tool in near surface geophysical surveys for investigation of various geological, environmental and engineering problems including landslide. Electrical Resistivity Method (ERM) is part of geophysical methods which used as preliminary step involve in any groundwater exploration. Electrical resistivity surveys have been used for many decades in hydro geological, mining and geotechnical investigations. APPLICATION OF THE ELECTRICAL RESISTIVITY METHOD IN ASSESSING SOIL FOR THE FOUNDATION OF BRIDGE STRUCTURES: A CASE STUDY FROM THE WARSAW ENVIRONS, POLAND Sebastian KOWALCZYK 1) *, Piotr ZAWRZYKRAJ 1), and Maciej MAŚLAKOWSKI 2) 1) Faculty of Geology, University of Warsaw, ul. Copyright © 2020 Elsevier B.V. or its licensors or contributors. According to Srinivasamoorthy (2009), the important purpose of electrical surveys is to determine the subsurface resistivity distribution by making measurements on the ground surface. This study presents that the developed ERM is effective to record soil moisture dynamics, especially in the near-surface zone, in small-scale evaporation tests. No plagiarism, guaranteed! View APPLICATIONS OF ELECTRICAL RESISTIVITY METHOD Research Papers on Academia.edu for free. Applications of Low Resistivity Materials: i. 2-D and even 3-D electrical surveys are now practical commercial method with the relatively nowadays advancement technology of multi-electrode resistivity surveying instruments (Griffiths et al. According to Lagmanson (2005), some properties which affect the resistivity of rock and soil are porosity,moisture content,dissolved electrolytes, temperature of pore water, and conductivity of minerals The proposed laboratory method. ( Binleyetal. From the current (I) and voltage (V) values, an apparent resistivity (pa) value is calculated. Noté /5. Because of this property, the Wenner array is relatively sensitive to vertical changes in the subsurface resistivity below the centre of the array. They are based on the principle that measurements of electrical potential at the surface depend on subsurface distributions of electrical resistivity (in Om). In dense sand, the resisting shear stress increases with shear displacement until it reaches a failure stress, ?f. It also provides insights on the potential of ERM in field applications to characterize soil hydraulic responses to drought climate. tous les mots . For instance, water supplies, fisheries, sewage disposal systems, forests, dams, and roadways can be affected for years after a slide event. As the chamber was subjected to drying, the evolutions of soil electrical resistance and water content at different depths were monitored continuously by the installed sixty electrodes and six time domain reflectometers (TDR) sensors, respectively. Soil electrical resistivity can be monitored using a variety of electrode configurations including one-, two- and four-electrode methods (Samson et … Hence, it is necessary to briefly describe the soil strength component of the work,as follows: The shearing behaviour of sand has so far been assumed to be isotropic; that is,the sand at a given density and mean stress level subject to any plane strain shear test has been assumed to have a unique peak angle of friction. For approximately the next 60 years, for quantitative interpretation, conventional sounding surveys (Koefoed 1979) were normally used. To determine the true subsurface resistivity, an inversion of the measured apparent resistivity values using a computer program must be carried out. ,2000). The apparatus described herein is relatively small and is suitable only for fine-grained soils, but larger apparatus can be used satisfactorily to test gravels. There were 13 major landslides reported in Malaysia, involving both cut and natural slopes with a total lost of more than 100 lives from 1993 to 2004,. The program might also assist the user in choosing the appropriate array for different geological situations or surveys. The Wenner array is usually applied for a good vertical resolution, but may also provide a reasonable horizontal resolution (Sasaki, 1992). Space techniques; remote sensing and GPS with its wide coverage are the proper candidate to put landslide and other natural disasters under surveillance. There are jungle trails, waterfalls, and flower nurseries, a very pleasant 9-hole golf course, and a riding stable. According to the paper by Symes (1983) and Tatsuoka (1987),for laboratory prepared samples on clean sand, the tangent of the plane strain angle of friction can vary by as much as 25% due to the orientation of shearing with respect to the bedding planes. … les mots exacts . Afterwards, the variations of soil water content at different depths were estimated based on the developed calibration relationship and compared with the TDR results. Fraser’s Hill located neatly at 1,524 meters above sea level, substantial to the north of the Genting Highlands and also in Pahang. The range of elevation in Fraser Hill is from 400 to 1300 meters above sea level. In Malaysia which is rapidly moving towards urbanization, many occurrences of landslides had been reported as a serious hazard which had fatalities and losses and results in severe damages in infrastructure. This program is largely intended for teaching about the use of the 2-D electrical imaging method. The resistivity measurements are normally made by injecting current into the ground through two current electrodes (C1 and C2 in figure 3.2), and measuring the resulting voltage difference at two potential electrodes (P1 and P2). The relationship between the “apparent” resistivity and the “true” resistivity is a complex relationship. Electrical resistivity/resistance method (ERM) The use of ERM refers to measuring soil apparent resistivity as a function of soil physical properties. Resistivity meters normally give a resistance value, R = V/I, so in practice the apparent resistivity value is calculated by. In the previous works,direct shear box had been used to determine the strength properties of the soil. The road to the hill resort winds for about 35 km after the Gap. According to the report by Jamaludin et al, 2006, serious natural landslides in this country normally occur in monsoon seasons where intense precipitation is the main triggering factor. In tropical climate such as Malaysia, the phenomenon is common especially in hilly areas during monsoon season. As evaporation continues, soil electrical resistance increases exponentially with decreasing water content. And according to Bujang B.K. The direct-shear test is one of the oldest methods for determining the shear strength of soil materials. Eventhough water itself is not a good conductor of electricity, ground water in most cases contains dissolved compounds that greatly improve its skill to conduct electricity. Line 1 gave almost identical shear strength results with line 2 but line 1 is prone to have landslides because of its slope degree higher than line 2. VAT Registration No: 842417633. Most of the area were consist of granite and higher resistivity indicate it has low saturated water. According to Gassim et al., (2001), the mean annual rainfall for the catchment is about 2624 mm with average of 208 rain- days in a year. Careful engineering and geologic study could then follow before such specific project could be implemented. The electrical resistivity method, which is one of the most widely practiced geophysical prospecting methods, has in the past usually been applied to groundwater and underground resource exploration. Practically all commercial multi-electrode systems come with the computer software to carry out this conversion. Majotiry of rock-forming minerals are electrical insulators although some native metals and graphite conduct electricity .The measured resistivities in earth materials are majorly controlled by the movement of charged ions in pore fluids. The difference between the maximum peak plane strain angle of friction which occurs when the sample is sheared across the bedding planes, and the minimum peak plane strain angle of friction which occurs when the sample is sheared along the bedding planes,is likely to depend on the soil particle shape and grading,and the method of soil deposition,among other factors. APPLICATIONS OF THE ELECTRICAL RESISTIVITY METHOD FOR DETECTION OF UNDERGROUND MINE WORKINGS by William J. Johnson – D’Appolonia, Monroeville, PA Introduction The need to understand the location of abandoned workings has recently been high-lighted by the failure of the Martin County Coal Corporation tailings impoundment near Inez, Kentucky on October 11, 2000 and the July 24, 2002 … Reference this. Previous studies include monitoring of groundwater ?ow by pro?ling or mapping the electrical response to an injected salinetracer, either lonely from the ground surface (White,1988,1994; Osiensky and Donaldson, 1995; Morrisetal., 1996) or in bore holes (Bevcand Morrison, 1991). However, there are still some uncertainties associated with stress level in the shear band; for this reason, stresses determined using boundary forces from this test are considered average stresses for the interface. Drought-induced evaporation can reduce soil water content and cause progressive desiccation cracking, which is responsible for various geotechnical and geo-environmental problems. The electrical resistivity method has been used to delineate shallow zones of ground‐water contamination resulting from solid waste disposal sites. 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