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The Effect of Sparger Geometry on Gas Bubble Flow Behaviors Using Electrical Resistance Tomography 被引量:13
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作者 靳海波 M. Wang R. A. Williams 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2006年第1期127-131,共5页
By electrical resistance tomography (ERT) the cross sectional profiles of gas hold-up in a φ56mm bubble column are obtained with four designs of gas sparger. The effect of sparger geometry on the bubble distribution ... By electrical resistance tomography (ERT) the cross sectional profiles of gas hold-up in a φ56mm bubble column are obtained with four designs of gas sparger. The effect of sparger geometry on the bubble distribution is re-vealed by applying a sensitivity conjugated gradients reconstruction method (SCG). Experimental results show that over-all hold-up obtained by ERT is generally in good agreement with those measured with the pressure transducer and the ERT system produces informative evidence that the radial profiles of hold-up is very similar to the sparger design in the lower section of bubble column. Meanwhile, the rise velocity of bubble swarm and the Sauter mean bubble size are evaluated using ERT based on dynamic gas disengagement theory. The experimental results are in good agreement with correlations and conventional estimation obtained using pressure transmitter methods. 展开更多
关键词 电阻层折成像技术 分布器 气泡柱 流动行为
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Detecting the Resistivity Distribution of Carbon Fiber Reinforced Concrete by Electrical Resistance Tomography Method
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作者 徐东亮 李卓球 +1 位作者 宋显辉 吕泳 《Journal of Southwest Jiaotong University(English Edition)》 2006年第4期323-330,共8页
According to the principle of electrical resistance tomography ( ERT), the resistivity distribution of the carbon fiber reinforced concrete (CFRC) in the sensing field can be measured by injecting exciting current... According to the principle of electrical resistance tomography ( ERT), the resistivity distribution of the carbon fiber reinforced concrete (CFRC) in the sensing field can be measured by injecting exciting current and measuring the voltage on the sensor electrode arrays installed on the surface of the object. Therefore, measurement of the resistivity distribution of CFRC is divided into first measuring the boundary conditions and then inversely computing the resistivity distribution. To reach this goal, an ERT system was constructed, which is composed of a sensor array unit, a data acquisition unit and an image reconstruction unit. Simulations of static ERT was performed on set-ups with many objects spread in a homogeneous background, and a simulation of dynamic ERT was also done on a rectangular board, the resistivity of which was changed within a small domain of it. Then, the resistivity distribution of a CFRC sample with a circlar hole as the target was detected by the ERT system. Simulation and experimental results show that the reconstructed ERT image reflects the resistivity distribution or the resistivity change of CFRC structure well. Especially, a small change in resistivity can be identified from the reconstructed images in the simulation of dynamic ERT images. 展开更多
关键词 electrical resistance tomography Carbon fiber reinforced concrete resistivity distribution detection
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Investigation of fractured rock aquifer in South China using electrical resistivity tomography and self-potential methods 被引量:5
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作者 Muhammad HASAN SHANG Yan-jun +1 位作者 JIN Wei-jun Gulraiz AKHTER 《Journal of Mountain Science》 SCIE CSCD 2019年第4期850-869,共20页
Assessment of fractured rock aquifers in many parts of the world is complicated given their strong heterogeneity. Delineation of the subsurface geological formation in the weathered terrain is essential for groundwate... Assessment of fractured rock aquifers in many parts of the world is complicated given their strong heterogeneity. Delineation of the subsurface geological formation in the weathered terrain is essential for groundwater exploration. To achieve this goal, 2D electrical resistivity tomography(ERT) and self-potential(SP) in combination with joint profile method(JPM) and boreholes have been carried out to delineate the subsurface geological units, detect the fracture/fault zones in hard rock, monitor the groundwater flow, and estimate the groundwater reserves contained within the weathered terrain at a complex heterogeneous site of Huangbu, South Guangdong of China. The integration of resistivity images with the borehole lithology along three profiles delineates three subsurface distinct layers namely topsoil cover, weathered and unweathered layers. The incorporation of ERT and SP with JPM reveal five fractures/faults, i.e., F_1, F_2, F_3, F_4 and F_5. 2D ERT models interpret the less resistive anomalies as the fractures/faults zones, and high resistive anomalies as the fresh bedrock. The inversion program based on the smoothness-constraint is used on the resistivity field data to get more realistic three layered model. SP measurements are obtained along the same electrical profiles which provide the negative anomalies clearly indicating the groundwater preferential flow pathways along the fracture/fault zones. Hydraulic parameters namely hydraulic conductivity and transmissivity were determined to estimate the groundwater resources contained within the fractures/faults. The integrated results suggest that the fractures/faults zones are most appropriate places of drilling for groundwater exploration in the investigated area. Geophysical methods coupled with the upfront borehole data provides better understanding about the conceptual model of the subsurface geological formations. The current investigation demonstrates the importance of the integrated geophysical methods as a complementary approach for groundwater assessment in the hard rock weathered areas. 展开更多
关键词 electrical resistIVITY tomography SELF-POTENTIAL Groundwater flow HARD rock HETEROGENEITY Hydraulic parameters
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Geophysical Investigation of a Solid Waste Disposal Site Using Integrated Electrical Resistivity Tomography and Multichannel Analyses of Surface Waves Methods 被引量:1
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作者 Ruobai Zhao Neil Anderson Jing Sun 《Journal of Geoscience and Environment Protection》 2020年第3期55-69,共15页
Electrical resistivity tomography survey was deployed at a solid waste landfill in southwest Missouri USA with the intent to map variations in moisture content through the solid waste and underlying subsurface, and to... Electrical resistivity tomography survey was deployed at a solid waste landfill in southwest Missouri USA with the intent to map variations in moisture content through the solid waste and underlying subsurface, and to map the top of bedrock. Multichannel analyses of surface waves survey was also deployed to map variations in engineering properties of the solid waste and underlying subsurface, and to constrain the interpretations of top of bedrock. The 2-D resistivity images through the waste suggest rainwater seeps through the cap cover system of the solid waste landfill, and moisture content within the solid waste increases with solid waste burial depth. The resistivity anomalies displayed by the soil and bedrock directly underneath the solid waste suggests a lateral component to moisture infiltrating at the toe of the landfill, which is flowing inward to the base of solid waste structural low. The 1-D shear wave velocity profiles obtained from the multichannel analyses of surface waves survey helped interpret the top of bedrock underneath the solid waste, where top of bedrock is difficult to map using electrical resistivity tomography, as shallow fractured bedrock is moist and displays comparable resistivity values to that of overlying soil. Not surprisingly, the top of bedrock is readily identified on the electrical resistivity tomography profiles in places where subsurface is relatively dry. The deployment of the combined non- invasive, cost and time effective geophysical surveys, along with engineering judgement on available site history data, has reasonably identified potential landfill seepage pathways. The methodology presented could be used in similar site investigation settings. 展开更多
关键词 electrical resistIVITY tomography electrical resistIVITY Imaging MULTICHANNEL ANALYSES of Surface Waves CCR Solid Waste LANDFILL CCR LANDFILL ert ERI MASW
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Contribution of Electrical Resistivity Tomography and Boring Technique in the Realization of Ten (10) Large Boreholes in a Crystalline Basement Rocks in the Centre-West of Benin 被引量:1
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作者 Nesny Yanonvoh Akokponhoué Nicaise Yalo +2 位作者 Bertrand Houngnigbo Akokponhoué Rita Houngue George Agbahoungba 《Journal of Geoscience and Environment Protection》 2019年第9期114-130,共17页
In order to ensure access to drinking water for Benin populations by 2021, the Emergency Measure program for the reinforcement of the drinking water supply system of Savalou city was initiated in 2018. This program fo... In order to ensure access to drinking water for Benin populations by 2021, the Emergency Measure program for the reinforcement of the drinking water supply system of Savalou city was initiated in 2018. This program focuses on densification and extension of hydraulic infrastructures. Therefore, it is prominent to use rigorous approach for implementation and execution of drilling activities. The present work has the advantage of combining the use of electrical resistivity tomography and borehole technique to locate ten high flow drilling in Savalou city. The electrical resistivity tomography (ERT) panels were made based on the dipole-dipole arrays with 48 electrodes with 5 m inter-electrode spacing. The drilling was carried out over ten selected points and in two stages: confirmation test using piezometer and borehole diameter enlargement. Moreover, only piezometers with flow rate greater than 10 m3/h were enlarged. The tomography processing has identified 10 fractured zones that are defined by 250 - 1000 ohm.m resistivity values and a width between 15 - 55 m. The confirmation test carried out over ten piezometers exhibits high flow rates ranging from 9 to 35 m3/h with depths of 30 to 68 m. Nine over the ten boreholes with a flow rate equal or greater than 10 m3/h, have improved their flow rates by 50% to 100% after the boring technique. Thus, the cumulative flow rate has reached 252. 7 m3/h for Savalou city and his surrounding areas. 展开更多
关键词 BORING Technique electrical resistIVITY tomography FRACTURES Savalou
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Nonlinear inversion for electrical resistivity tomography based on chaotic DE-BP algorithm 被引量:3
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作者 戴前伟 江沸菠 董莉 《Journal of Central South University》 SCIE EI CAS 2014年第5期2018-2025,共8页
Nonlinear resistivity inversion requires efficient artificial neural network(ANN)model for better inversion results.An evolutionary BP neural network(BPNN)approach based on differential evolution(DE)algorithm was pres... Nonlinear resistivity inversion requires efficient artificial neural network(ANN)model for better inversion results.An evolutionary BP neural network(BPNN)approach based on differential evolution(DE)algorithm was presented,which was able to improve global search ability for resistivity tomography 2-D nonlinear inversion.In the proposed method,Tent equation was applied to obtain automatic parameter settings in DE and the restricted parameter Fcrit was used to enhance the ability of converging to global optimum.An implementation of proposed DE-BPNN was given,the network had one hidden layer with 52 nodes and it was trained on 36 datasets and tested on another 4 synthetic datasets.Two abnormity models were used to verify the feasibility and effectiveness of the proposed method,the results show that the proposed DE-BP algorithm has better performance than BP,conventional DE-BP and other chaotic DE-BP methods in stability and accuracy,and higher imaging quality than least square inversion. 展开更多
关键词 非线性反演 电阻率成像法 BP算法 人工神经网络 BP神经网络 全局搜索能力 混沌 最小二乘反演
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Comparison of smoothness-constrained and geostatistically based cross-borehole electrical resistivity tomography for characterization of solute tracer plumes
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作者 Andreas Englert Andreas Kemna +3 位作者 Jun-feng Zhu Jan Vanderborght Harry Vereecken Tian-Chyi J.Yeh 《Water Science and Engineering》 EI CAS CSCD 2016年第4期274-286,共13页
Experiments using electrical resistivity tomography(ERT) have shown promising results in reducing the uncertainty of solute plume characteristics related to estimates based on the analysis of local point measurements ... Experiments using electrical resistivity tomography(ERT) have shown promising results in reducing the uncertainty of solute plume characteristics related to estimates based on the analysis of local point measurements only.To explore the similarities and differences between two cross-borehole ERT inversion approaches for characterizing salt tracer plumes,namely the classical smoothness-constrained inversion and a geostatistically based approach,we performed two-dimensional synthetic experiments.Simplifying assumptions about the solute transport model and the electrical forward and inverse model allowed us to study the sensitivity of the ERT inversion approaches towards a variety of basic conditions,including the number of boreholes,measurement schemes,contrast between the plume and background electrical conductivity,use of a priori knowledge,and point conditioning.The results show that geostatistically based and smoothness-constrained inversions of electrical resistance data yield plume characteristics of similar quality,which can be further improved when point measurements are incorporated and advantageous measurement schemes are chosen.As expected,an increased number of boreholes included in the ERT measurement layout can highly improve the quality of inferred plume characteristics,while in this case the benefits of point conditioning and advantageous measurement schemes diminish.Both ERT inversion approaches are similarly sensitive to the noise level of the data and the contrast between the solute plume and background electrical conductivity,and robust with regard to biased input parameters,such as mean concentration,variance,and correlation length of the plume.Although sophisticated inversion schemes have recently become available,in which flow and transport as well as electrical forward models are coupled,these schemes effectively rely on a relatively simple geometrical parameterization of the hydrogeological model.Therefore,we believe that standard uncoupled ERT inverse approaches,like the ones discussed and assessed in this paper,will continue to be important to the imaging and characterization of solute plumes in many real-world applications. 展开更多
关键词 electrical resistIVITY tomography Inversion technique SOLUTE TRACER PLUME Synthetic experiment PLUME characteristics
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Hydrate formation and distribution within unconsolidated sediment:Insights from laboratory electrical resistivity tomography
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作者 Yanlong Li Nengyou Wu +5 位作者 Changling Liu Qiang Chen Fulong Ning Shuoshi Wang Gaowei Hu Deli Gao 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2022年第9期127-136,共10页
Laboratory visual detection on the hydrate accumulation process provides an effective and low-cost method to uncover hydrate accumulation mechanisms in nature.However,the spatial hydrate distribution and its dynamic e... Laboratory visual detection on the hydrate accumulation process provides an effective and low-cost method to uncover hydrate accumulation mechanisms in nature.However,the spatial hydrate distribution and its dynamic evolutionary behaviors are still not fully understood due to the lack of methods and experimental systems.Toward this goal,we built a two-dimensional electrical resistivity tomography(ERT)apparatus capable of measuring spatial and temporal characteristics of hydrate-bearing porous media.Beach sand(0.05–0.85 mm)was used to form artificial methane hydrate-bearing sediment.The experiments were conducted at 1°C under excess water conditions and the ERT data were acquired and analyzed.This study demonstrates the utility of the ERT method for hydrate mapping in laboratory-scale.The results indicate that the average electrical conductivity decreases nonlinearly with the formation of the hydrate.At some special time-intervals,the average conductivity fluctuates within a certain scope.The plane conductivity fields evolve heterogeneously and the local preferential hydrate-forming positions alternate throughout the experimental duration.We speculate that the combination of hydrate formation itself and salt-removal effect plays a dominant role in the spatial and temporal hydrate distribution,as well as geophysical parameters changing behaviors during hydrate accumulation. 展开更多
关键词 natural gas hydrate electrical resistivity electrical resistivity tomography accumulation mechanism electrical conductivity
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Electrical Resistivity Tomography and TDEM Applied to Hydrogeological Study in TaubatéBasin, Brazil
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作者 Rodrigo Corrêa Rangel Jorge Luís Porsani +1 位作者 Cassiano Antonio Bortolozo Luiz Rodrigo Hamada 《International Journal of Geosciences》 2018年第2期119-130,共12页
This research applies Electrical Resistivity Tomography (ERT) and Time Domain Electromagnetic Method (TDEM) to study the hydrogeology of the Taubaté basin, which is characterized by half-grabens with about 850 m ... This research applies Electrical Resistivity Tomography (ERT) and Time Domain Electromagnetic Method (TDEM) to study the hydrogeology of the Taubaté basin, which is characterized by half-grabens with about 850 m of maximum sediments thickness. The study area is in Taubaté city, S&atilde;o Paulo State, Brazil, where the Taubaté aquifer is an important water source. The Taubaté Group is the main sedimentary package of the basin;it is formed mainly by shales that form aquicludes, and thin layers of sandstones that form the aquifer. There are 40 groundwater exploration wells in Taubaté city that provide important information. The study purpose is to characterize the geoelectrical stratigraphy of the subsurface to locate the contact between the Quaternary and Tertiary sediments and to identify the Taubaté aquifer. The ERT is used for shallow investigations (tens of meters) and the TDEM can reach a great investigation depth (hundreds of meters). Therefore, these geophysical methods are complementary. The ERT data were acquired with the pole-dipole array with 20 m of electrodes spacing and 400 m length, and the TDEM data with the central-loop array with a 200 × 200 m transmitter loop. The results permit to define the contact between the Quaternary and Tertiary sediments around 15 m depth, the Pindamonhangaba Formation between 15 m and 30 m depth and the Taubate Group between 30 m and 300 m depth. The TDEM method defined the Taubaté Group as a single geoelectric layer because the shale and the sandstone layers are all very conductive. The basement is formed by gneiss, which is a very resistive rock. The TDEM method is not able to identify a high conductor/resistor contrast. Overall, the results are consistent with the known geology and the wells information. 展开更多
关键词 electrical resistIVITY tomography (ert) Time Domain electromagnetic (TDEM) HYDROGEOPHYSICS Taubaté BASIN Brazil
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Mapping Subsurface Seepage Flow Patterns in Proximity to a Coal Combustion Residual Landfill Using Electrical Resistivity Tomography
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作者 Ruobai Zhao Neil Anderson +2 位作者 David Rogers Evgeniy Torgashov Jing Sun 《Journal of Geoscience and Environment Protection》 2021年第2期144-157,共14页
Electrical resistivity tomography data were acquired in proximity to the coal combustion residual landfill in an effort to image and analyze seepage pathways through the shallow residual soil and underlying karsted li... Electrical resistivity tomography data were acquired in proximity to the coal combustion residual landfill in an effort to image and analyze seepage pathways through the shallow residual soil and underlying karsted limestone bedrock. The water table is at a depth of more than 45 m. The most prominent subsurface seepage pathways identified on the acquired electrical resistivity tomography data are located immediately adjacent to the toe of the landfill and are attributed to stormwater run-off. The moisture content of the limestone appears to decrease gradually with increasing distance from the toe of the landfill, suggesting there is also a horizontal component of moisture flow in the subsurface. Shallow limestone with higher moisture content generally underlies or is in close proximity to anthropogenic features such as drainage ditches and clay berms that are designed to channel run-off. At one location, electrical resistivity tomography data were acquired along essentially the same traverse at different times of the year, and the resistivity of shallow limestone overall was lower on the data acquired after heavy rains. 展开更多
关键词 Coal Ash electrical resistivity tomography (ert) SEEPAGE Solid Waste Landfill Geophysical Methods Coal Combustion Residual (CCR)
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Characterisation of Fractures and Fracture Zones in a Carbonate Aquifer Using Electrical Resistivity Tomography and Pricking Probe Methodes
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作者 Sándor Szalai Attila Kovács +4 位作者 Lukács Kuslits Gábor Facskó Katalin Gribovszki János Kalmár László Szarka 《Journal of Geoscience and Environment Protection》 2018年第4期1-21,共21页
Position, width and fragmentation level of fracture zones and position, sig-nificance and characteristic distance of fractures were aimed to determine in a carbonate aquifer. These are fundamental parameters, e.g. in ... Position, width and fragmentation level of fracture zones and position, sig-nificance and characteristic distance of fractures were aimed to determine in a carbonate aquifer. These are fundamental parameters, e.g. in hydrogeological modelling of aquifers, due to their role in subsurface water movements. The description of small scale fracture systems is however a challenging task. In the test area (Kádárta, Bakony Mts, Hungary), two methods proved to be applicable to get reasonable information about the fractures: Electrical Resistivity Tomography (ERT) and Pricking-Probe (PriP). PriP is a simple mechanical tool which has been successfully applied in archaeological investigations. ERT results demonstrated its applicability in this small scale fracture study. PriP proved to be a good verification tool both for fracture zone mapping and detecting fractures, but in certain areas, it produced different results than the ERT. The applicability of this method has therefore to be tested yet, although its problems most probably origin from human activity which reorganises the near-surface debris distribution. In the test site, both methods displayed fracture zones including a very characteristic one and a number of individual fractures and determined their characteristic distance and significance. Both methods prove to be able to produce hydrogeologically important parameters even individually, but their simultaneous application is recommended to decrease the possible discrepancies. 展开更多
关键词 KARST FRACTURE FRACTURE ZONE electrical resistIVITY tomography Pricking Probe
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Exploration on electrical resistance tomography in characterizing the slurry spatial distribution in cemented granular materials
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作者 Bohao WANG Wei WANG +3 位作者 Feng JIN Handong TAN Ning LIU Duruo HUANG 《Frontiers of Structural and Civil Engineering》 SCIE EI CSCD 2024年第3期365-379,共15页
This study investigated the application of electrical resistance tomography(ERT)in characterizing the slurry spatial distribution in cemented granular materials(CGMs).For CGM formed by self-flow grouting,the voids in ... This study investigated the application of electrical resistance tomography(ERT)in characterizing the slurry spatial distribution in cemented granular materials(CGMs).For CGM formed by self-flow grouting,the voids in the accumulation are only partially filled and the bond strength is often limited,which results in difficulty in obtaining in situ samples for quality evaluation.Therefore,it is usually infeasible to evaluate the grouting effect or monitor the slurry spatial distribution by a mechanical method.In this research,the process of grouting cement paste into high alumina ceramic beads(HACB)accumulation is reliably monitored with ERT.It shows that ERT results can be used to calculate the cement paste volume in the HACB accumulation,based on calibrating the saturation exponent n in Archie’s law.The results support the feasibility of ERT as an imaging tool in CGM characterization and may provide guidance for engineering applications in the future. 展开更多
关键词 electrical resistance tomography cemented granular material GROUTING spatial distribution Archie’s law
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Application of 3D Electrical Resistivity Tomography for Diagnosing Leakage in Earth Rock-Fill Dam
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作者 Xin Zhang Mingjie Zhao +2 位作者 Kui Wang Pan Liu Huan Liu 《Engineering(科研)》 2016年第5期269-275,共7页
The leakage occurs during operation of the dam in Liuhuanggou reservoir. It’s a threat to the safety of the people’s lives and property in downstream. In order to eliminate the hidden danger of reservoir, ensure the... The leakage occurs during operation of the dam in Liuhuanggou reservoir. It’s a threat to the safety of the people’s lives and property in downstream. In order to eliminate the hidden danger of reservoir, ensure the safety of the dam, play better the function of flood control and water storage of the reservoir etc., we apply the 3D electrical resistivity tomography detecting technology and volume rendering image processing technology, make the measurement in field, process the data and combine the field survey to find out the leakage channels inside the dam. The results show that the 3D resistivity images appear the low resistivity zone corresponding with the leakage channels. There are two main leakage channels that come from different location inside the dam. It is feasible to diagnose the leakage in earth rock-fill dam by applying 3D electrical resistivity tomography. 展开更多
关键词 Earth Rock-Fill Dam LEAKAGE 3D electrical resistivity tomography Volume Rendering
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Numerical Simulation Study on the Detection of Weak Structural Plane of Rock Slope by Using 3D Electrical Resistivity Tomography
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作者 Xin Zhang 《Engineering(科研)》 2016年第7期438-444,共8页
The weak structure plane is an important factor affecting the stability of rock slope, and detecting the spatial structure of the weak structural plane is beneficial to analyze the stability of the slope and estimate ... The weak structure plane is an important factor affecting the stability of rock slope, and detecting the spatial structure of the weak structural plane is beneficial to analyze the stability of the slope and estimate the quantity of the landslide. Based on 3D electrical resistivity tomography, a model of rock slope with weak structure plane is established, and the characteristics of three-dimensional resistivity imaging of weak structure plane under different ground water conditions are simulated. The results show that the weak structural plane has a better reflection in 3D electrical resistivity tomography;the distribution of weak structural plane of 3D resistivity imaging can be roughly determined under different ground water conditions;the three-dimensional electrical resistivity tomography is feasible in the detection of weak structural plane of rock slope. 展开更多
关键词 Rock Slope Soft Structure Plane 3D electrical resistivity tomography Numerical Simulation
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Comparison of laboratory and field electrical resistivity measurements of a gypsum rock for mining prospection applications 被引量:2
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作者 Chiara Caselle Sabrina Bonetto Cesare Comina 《International Journal of Mining Science and Technology》 SCIE EI CSCD 2019年第6期841-849,共9页
Geophysical surveys are frequently applied in mining prospection to detect the presence and volume of ore bodies of different nature.Particularly,in gypsum ore bodies exploitation,electrical resistivity measurements a... Geophysical surveys are frequently applied in mining prospection to detect the presence and volume of ore bodies of different nature.Particularly,in gypsum ore bodies exploitation,electrical resistivity measurements are usually the most used methodology.However,it has been observed that different electrical resistivity values can be obtained depending on geometrical features and composition of gypsum.Indeed,electrical resistivity of gypsum rocks depends on several parameters,such as gypsum purity,nature of secondary minerals,porosity,saturation and interstitial fluid properties.Saturation and hydrogeological setting,in particular,were recognized as the most influencing parameters.Hydrogeological conditions of gypsum rock masses are also very relevant for exploitability,safety conditions and economic feasibility and should be accurately known during the prospection and planning phases of the quarries.In this work,a relationship between electrical resistivity and saturation degree of gypsum is proposed.The possibility to estimate gypsum porosity with the use of this relationship is also investigated.The reliability of laboratory measurements is finally verified in comparison with field and modelled resistivity data.The reported results underline the potentiality of the proposed approach to obtain a reliable characterization of the studied ore body. 展开更多
关键词 GYPSUM ROCK electrical resistIVITY Saturation Porosity ARCHIE ert QUARRY
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基于ERT技术反演红壤剖面水分入渗过程
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作者 田园 钟雪梅 +2 位作者 彭新华 汪亚及 高磊 《土壤学报》 CAS CSCD 北大核心 2024年第3期714-726,共13页
水分运动是土壤中物质和能量传输的主要驱动力,但是水分在土壤中的运动轨迹复杂多变,难以直接捕捉。本研究以第四纪红黏土发育的红壤为研究对象,借助电阻率成像技术(ERT),反演水分在林地和农地土壤中的入渗过程。研究发现,ERT技术能够... 水分运动是土壤中物质和能量传输的主要驱动力,但是水分在土壤中的运动轨迹复杂多变,难以直接捕捉。本研究以第四纪红黏土发育的红壤为研究对象,借助电阻率成像技术(ERT),反演水分在林地和农地土壤中的入渗过程。研究发现,ERT技术能够实现水分在红壤包气带入渗过程的可视化,ERT测定的表观电阻率的变化量与烘干法测定的土壤水分之间呈极显著正相关关系(P<0.01),林地的决定系数为0.72,农地为0.53。土地利用类型影响水分入渗的范围和方式,在2 cm水头高度注水100 L的情况下,林地的入渗深度大于80 cm,而农地约为50 cm,在此基础上,继续注水200 min,林地和农地均出现明显的优先流现象。但是,林地的优先流较农地更为发育,林地是通过根系等大孔隙快速向下传输,而农地则以“指流”的方式,间断性向深层运动。在土壤层次复杂、背景含水量高、土壤黏重等不利因素的影响下,ERT技术依然能捕捉优先流在红壤中发生和发育的过程。 展开更多
关键词 电阻率层析成像技术 土地利用类型 红黏土 土壤水分 优先流
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Electrical geophysical evaluation of susceptibility to flooding in University of Nigeria, Nsukka main campus and its environs, Southeastern Nigeria
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作者 Daniel Nnaemeka Obiora Johnson Cletus Ibuot 《Journal of Groundwater Science and Engineering》 2023年第4期422-434,共13页
Flooding occurs when rainfall exceeds the absorption capacity of soil and causes significant environmental consequences.In this study,electrical resistivity techniques were employed to assess the flood susceptibility ... Flooding occurs when rainfall exceeds the absorption capacity of soil and causes significant environmental consequences.In this study,electrical resistivity techniques were employed to assess the flood susceptibility of the study area by examining variations in electrical properties.Prior to flooding,Vertical Electrical Sounding(VES)and Electrical Resistivity Tomography(ERT)profiles were conducted to determine the variations in resistivity within subsurface lithologies exposed to the injected current.The injected current penetrated the subsurface units characterised by resistivity ranging from 190.5Ω·m to 6,775.7Ω·m,42.3Ω·m to 7,297.4Ω·m,and 320.2Ω·m to 24,433.3Ω·m in the first,second and third layers,respectively.These layers were identified as lateritic topsoil,medium-coarse brownish grained sand,and coarse pebbly blackish sand,respectively.The calculated reflection coefficients between layers 1,2,and 3 reveal alternation in layers with values ranging from−0.04 to 0.66 and 0.36 to 0.95 for and,respectively.The transverse resistivity,longitudinal resistivity and anisotropy ranged from 243.59Ω·m to 24,115.42Ω·m,199.61Ω·m to 14,950.76Ω·m,and 1.02 to 2.14.Models derived from the ERT profiles reveal variations in resistivity,pinpointing areas of low resistivity which correspond to waterlogged and impermeable layers.The result of this study underscores the importance of integrated resistivity techniques in the study of floods,as it provides valuable insights into flood behaviour,and subsurface dynamics. 展开更多
关键词 ANISOTROPY Vertical electrical sounding electrical resistivity tomography Geoelectric layer Permeability
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面向ERT大面积触觉传感的自适应优化成像方法
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作者 郑文栋 刘华平 孙富春 《测控技术》 2024年第4期21-28,共8页
在动态的非结构化环境中,有效地感知物理接触对于智能机器人安全交互至关重要。为了能够检测各种潜在的物理交互,需要在机器人表面部署大面积触觉传感器。目前,现有的大面积触觉传感器主要是通过传感阵列方式实现的,但是大规模部署传感... 在动态的非结构化环境中,有效地感知物理接触对于智能机器人安全交互至关重要。为了能够检测各种潜在的物理交互,需要在机器人表面部署大面积触觉传感器。目前,现有的大面积触觉传感器主要是通过传感阵列方式实现的,但是大规模部署传感元件在实际应用中存在巨大挑战。电阻层析成像(Electrical Resistance Tomography,ERT)技术作为一种连续传感方式,有望克服传统触觉传感阵列的一些限制。为此,利用ERT设计了一款新型的大面积触觉传感器。在此基础上,提出了一种基于自适应感兴趣区(Region of Interest,ROI)的图像重构算法,将图像重构限制在交互区域内,以提高传感器的空间分辨率。为了验证提出成像算法的有效性,通过仿真与物理实验对其进行了全面评估。实验验证了该算法可以有效提高触觉传感器在交互区域的空间分辨率,使其具有较高的测量精度。实验结果表明,该传感器的平均定位误差为0.823 cm,能够准确地识别8种不同交互模式,其精度高达98.6%。这一研究工作表明,该传感器为机器人具身触觉传感的实现提供了一个新的解决方案。 展开更多
关键词 大面积触觉传感 电阻层析成像 机器人触觉感知 人机交互 图像重建
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Application of Electrical Tomography to Put in Evidence the Thickness and Structure of the Filling of Dayet Iffer (Middle Atlas, Morocco)
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作者 Bouchra Lemdeghri Alaoui Abdennasser Baali +2 位作者 Mohamed Chibout Anasse Benslimane Fatima Zahra Faqihi 《International Journal of Geosciences》 2020年第4期170-183,共14页
The Dayet Iffer belongs to the Dayets of tectono-karst origin of the Northern Middle Atlas. After its watershed genesis of middle altitude during the Quaternary, two lacustrine formations were deposited on the surface... The Dayet Iffer belongs to the Dayets of tectono-karst origin of the Northern Middle Atlas. After its watershed genesis of middle altitude during the Quaternary, two lacustrine formations were deposited on the surface while other thick formations exist in depth. The detailed sedimentological study of the soltanian and holocene lithological sections on the surface and the 14C datings helped recognize part of the history of the watershed. The geophysical study allowed to detect the thickness of the superficial geological formations as well as the various geological phenomena (tectonic and/or karst) that affected them from the genesis to the present. The current shape of the watershed where the Dayet Iffer exists is only the result of an evolution where sedimentary, tectonic and karst phenomena interfere. The tomography obtained with Res2DInv software, performed for the first time at the Dayet Iffer, reveals the presence of three ranges which can be interpreted as three resistive, intermediate and conductive zones with a large set of faults. These results helped determine the thickness (over 160 m) of the sedimentary filling. This shows that the hydrological behavior of the Dayet Iffer takes into account both horizontal flows at the stratification and/or karstic joints and the movement of sub-vertical fractures. 展开更多
关键词 electrical tomography resistIVITY LACUSTRINE SEDIMENTS Dayet QUATERNARY Middle Atlas
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Integrated Geoelectrical Resistivity Method for Environmental Assessment of Landfill Leachate Pollution and Aquifer Vulnerability Studies
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作者 Stanley U. Eze Omafume M. Orji +2 位作者 Abriku E. Onoriode Saleh A. Saleh Macpaul O. Abolarin 《Journal of Geoscience and Environment Protection》 2022年第9期1-26,共26页
Leachate plumes from landfills are a major source of pollution in Nigeria, especially in urban areas. Assessing leachate contamination in the subsoil is considered a complex process that needs detailed field measureme... Leachate plumes from landfills are a major source of pollution in Nigeria, especially in urban areas. Assessing leachate contamination in the subsoil is considered a complex process that needs detailed field measurement to accurately define the extent of contamination. To ascertain the extent of pollution of the subsoil and groundwater sources which were reportedly contaminated by leachate plumes from an old dumpsite located in Osubi town, an integrated geo-electrical method involving 1-D vertical electrical sounding (VES) and 2-D, 3-D ERT techniques were employed. Orthogonal set of 2-D apparent resistivity data was collected in a 100 × 50 m<sup>2</sup> rectangular grid around the dumpsite, using the Wenner array. Two years later, three (3) 2-D resistivity imaging profiles were also recorded in time-lapse mode at the dumpsite to monitor the possible effects of attenuation on the leachate over time. Ten (10) VES data were also acquired and used along with the 2-D imaging data. 2-D apparent resistivity data were inverted with Dipprowin software program. The orthogonal set of 2-D lines of apparent resistivity was merged into 3-D data and inverted with RES3DINV program to create a 3-D subsurface resistivity model. Geological models observed from 2-D and 3-D resistivity inversion revealed low resistivity values in the order ρ Ω·m which is indicative of leachate plumes in the saturation zone (pore water). The 2-D resistivity-depth sections imaged low resistivity leachate plumes at the near surface (<5 m) to a depth of 25.0 m, while 3-D inversion depth slices imaged leachate contaminant within the first, second and third layers at depth ranging from 0.00 - 2.50 m, 2.50 - 5.38 m and 5.38 - 8.68 m respectively. Thus, leachate contamination clearly increased with depth beyond the depth of first and second aquifers in the area which implies that available groundwater for domestic use is already contaminated with leachate from the dumpsite. Leachate contaminant-depth map estimated for the second geoelectric layers for VES 2, 3, 4, 7, 8, 9, and 10 shows that the second layer has been invaded completely by leachate contamination up to 6.5 m depth. 2-D apparent resistivity data acquired two years after show lower resistivity anomalies of the leachate plume caused by time-lapse attenuation effect on the observed resistivity of the leachate. This indicates that the leachate plume has become more conductive and toxic to the environment. The Longitudinal conductance map of the area shows that the aquifer protective capacity of this area is weak (0.1 - 0.19 Mho) thus, aquifers in the area are prone to pollution from the dumpsite. The three techniques used in this study (2-D, 3-D ERT and 1-D VES) fitly provided crucial information on the degree of contamination caused by the landfill leachate plume. Therefore, it is advisable to implement an environmental remediation and leachate management program. 展开更多
关键词 Leachate Contamination Groundwater Pollution 2D and 3D electrical resistivity tomography (ert) Aquifer Vulnerability Environmental Assessment
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