Détermination de la géométrie et des propriétés physiques du pergélisol discontinu de la région de Schefferville

1977 ◽  
Vol 14 (3) ◽  
pp. 431-443 ◽  
Author(s):  
Maurice K.-Seguin
Keyword(s):  
Electrical Resistivity ◽  
Regional Scale ◽  
Seismic Refraction ◽  
Geophysical Methods ◽  
Near Surface ◽  
Vertical Extension ◽  
Discontinuous Permafrost ◽  
Propriétés Physiques ◽  
Lower Limits

The various parameters used to predict on a regional scale the lateral and vertical extension of permafrost are the following: surface temperature, thermal conductivity of rocks, and geothermal flow configuration. Locally this type of data is generally not sufficient and far too inaccurate. The use of geophysical methods at the surface and in boreholes in addition to existing thermal data helps to improve the degree of accuracy in the prediction of spatial distribution of permafrost in a given area. These geophysical methods include seismic refraction, electrical resistivity, and spontaneous and induced polarizations.Because of the properties of permafrost, seismic refraction at surface is useful only to determine the top of the permafrost whereas electrical resistivity (electric logging near surface) allows the determination of the upper and lower limits of permafrost. Seismic refraction, resistivity, and spontaneous and induced polarizations in boreholes were deemed more promising to determine masses or lenses of permafrost.Moreover, it was possible to correlate temperature and electrical resistivity measurements in boreholes, thus allowing the drawing of isothermal curves from electric logging in areas of continuous and discontinuous permafrost, at least when it is 'marginal'.The data for this study were obtained from the experimental station at Schefferville, Québec. [Journal Translation]

scholarly journals Mapping the Distribution of Buried Glacier Ice – An Example From Lago Delle Locce, Monte Rosa, Italian Alps

1986 ◽  
Vol 8 ◽  
pp. 78-81 ◽  
Author(s):  
W. Haeberli ◽  
F. Epifani
Keyword(s):  
Snow Cover ◽  
Seismic Refraction ◽  
Italian Alps ◽  
Frozen Ground ◽  
Near Surface ◽  
Winter Snow ◽  
Glacier Ice ◽  
Geoelectrical Resistivity ◽  
Monte Rosa

Techniques for mapping the distribution of buried glacier ice are discussed and the results, from a study carried out within the framework of flood protection work in the Italian Alps, are presented. Bottom temperatures of the winter snow cover (BTS) primarily indicate the heat flow conditions in the underlying ground and mainly depend on the presence or absence of an ice layer beneath the surface. Determination of BTS values is therefore an inexpensive method for quickly mapping the near-surface underground ice in areas where there is 1 m or more of winter snow cover. At greater depths, and/or when more detail is required, geoelectrical resistivity soundings and seismic refraction soundings are most commonly used to investigate underground ice. A combination of the two sounding techniques allows the vertical extent and the main characteristics (frozen ground, dead glacier ice) to be determined in at least a semi-quantitative way. Complications mainly arise from irregularity in the horizontal extension of the studied underground ice bodies, and they may have to be overcome by expensive core drillings and borehole measurements. Widespread occurrence of buried glacier ice was observed in morainic deposits, surrounding an ice-dammed lake near Macugnaga, Italy.

scholarly journals DETERMINATION OF PRODUCTION WELL'S COLLECTORS POROSITY IN SOUTH-GEOLOGICAL AREA

2016 ◽  
pp. 25-29
Author(s):  
G. E. Stroyanetskaya
Keyword(s):  
Electrical Resistivity ◽  
Geophysical Methods ◽  
Caliper Measurement ◽  
Porosity Coefficient

The problems of collectors at the stage of calculating the reserves in operating incline directional wells, penetrated on clay, polymer-clay solution, polymer washing liquid with hydrochloric-calcium foundation were considered. The electrical resistivity of the solution and the washing liquid from 0.1 to 1 O·mm. According to geophysical methods, establishing of the criteria for the allocation of the collectors requires coring. The main methods for the isolation of collectors are lateral, microlaterolog survey and caliper measurement. The techniques of the gas-saturated collectors porosity coefficient determination were considered.

scholarly journals The Usefulness of Seismic Surveys for Geotechnical Engineering in Karst: Some Practical Examples

Geosciences ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 406
Author(s):  
Mario Bačić ◽  
Lovorka Librić ◽  
Danijela Jurić Kaćunić ◽  
Meho Saša Kovačević
Keyword(s):  
Large Strain ◽  
Geotechnical Engineering ◽  
Geophysical Methods ◽  
Near Surface ◽  
Distinctive Features ◽  
Seismic Surveys ◽  
Karstic Features ◽  
Engineering Investigation ◽  
Control Campaign

Having in mind uncertainties linked with the nature of rock masses, it is a challenge for geotechnical engineers to characterize them in a credible manner, especially if the rock mass in question is a notoriously complex karst with its distinctive features such as voids and discontinuities. A large range of geophysical methods are useful tools in the characterization efforts and their utilization in karst environments nowadays is a non-negotiable requirement, even though near-surface scattering significantly affects the acquired data. This paper demonstrates the versatile applications of seismic geophysical methods for geotechnical engineering in karst, from mapping of near-surface karstic features to the application of elastic wave velocities in determination of small to large strain stiffness of karst. The highlighted practical examples offer a step forward from the traditional interpretation of seismic surveys, making them a prosperous tool in geotechnical engineering investigation works, design and quality control campaign.

scholarly journals CRSP, numerical results for an electrical resistivity array to detect underground cavities

2017 ◽  
Vol 9 (1) ◽  
Author(s):  
Amin Amini ◽  
Hamidreza Ramazi
Keyword(s):  
Electrical Resistivity ◽  
Geophysical Methods ◽  
Electrode Array ◽  
Electrode Configuration ◽  
Electrode Arrays ◽  
Wide Range ◽  
Underground Cavities ◽  
Conventional Electrode

AbstractThis paper is devoted to the application of the Combined Resistivity Sounding and Profiling electrode configuration (CRSP) to detect underground cavities. Electrical resistivity surveying is among the most favorite geophysical methods due to its nondestructive and economical properties in a wide range of geosciences. Several types of the electrode arrays are applied to detect different certain objectives. In one hand, the electrode array plays an important role in determination of output resolution and depth of investigations in all resistivity surveys. On the other hand, they have their own merits and demerits in terms of depth of investigations, signal strength, and sensitivity to resistivity variations. In this article several synthetic models, simulating different conditions of cavity occurrence, were used to examine the responses of some conventional electrode arrays and also CRSP array. The results showed that CRSP electrode configuration can detect the desired objectives with a higher resolution rather than some other types of arrays. Also a field case study was discussed in which electrical resistivity approach was conducted in Abshenasan expressway (Tehran, Iran) U-turn bridge site for detecting potential cavities and/or filling loose materials. The results led to detect an aqueduct tunnel passing beneath the study area.

Geophysical mapping of gypsum for exploration of reserves in the Nong Bua area of Thailand

2020 ◽  
pp. qjegh2019-180
Author(s):  
Rungroj Arjwech ◽  
Mark E. Everett ◽  
Sakhon Saengchomphu ◽  
Kittipong Somchat ◽  
Potpreecha Pondthai
Keyword(s):  
Electrical Resistivity ◽  
Construction Projects ◽  
Seismic Refraction ◽  
Geophysical Methods ◽  
Raw Material ◽  
P Wave ◽  
The Core ◽  
Micro Cracks ◽  
P Wave Velocity ◽  
Increasing Demand

The increasing demand for gypsum as a raw material for construction projects motivates exploration for additional reserves. Electrical resistivity tomography (ERT) and seismic refraction geophysical methods, augmented with borehole and laboratory measurements on core samples, are used here to delineate the top, bottom and lateral boundaries of an important gypsum ore deposit in Thailand, an economically developing region. The gypsum-bearing formation is found throughout the study area to have an irregular upper boundary on account of karstic dissolution processes. The deeper transition from gypsum to anhydrite, however, is not constrained by the measurements. The P-wave velocity measured in the field is consistent with the core specimen measurements. The electrical resistivity of the core specimens, however, is substantially higher than the values measured in the field. The specimen measurements may depend on the presence of micro cracks, whereas electrical resistivity in the field may be affected by the enclosing clay-rich materials.

Geophysical characterization of inactive/active rock glaciers in the semi-arid Andes using seismic, geoelectrics and GPR

2020 ◽  
Author(s):  
remi valois ◽  
Nicole Schafer ◽  
Giulia De Pasquale ◽  
Gonzalo Navarro ◽  
Shelley MacDonell
Keyword(s):  
Electrical Resistivity ◽  
Seismic Velocity ◽  
Seismic Refraction ◽  
Geophysical Methods ◽  
Late Summer ◽  
Relevant Information ◽  
Refraction Tomography ◽  
Rock Glaciers ◽  
Ice Content ◽  
Ground Penetrating

<p>Rock glaciers play an important hydrological role in the semiarid Andes (SA; 27º-35ºS). They cover about three times the area of uncovered glaciers and they are an important contribution to streamflow when water is needed most, especially during dry years and in the late summer months. Their characteristics such as their extension in depth and their ice content is poorly known. Here, we present a case study of one active rock glacier and periglacial inactive geoform in Estero Derecho (~30˚S), in the upper Elqui River catchment, Chile. Three geophysical methods (ground-penetrating radar and electrical resistivity and seismic refraction tomography) were combined to detect the presence of ice and understand the internal structure of the landform. The results suggest that the combination of electrical resistivity and seismic velocity provide relevant information on ice presence and their geometry. Radargrams shows diffraction linked to boulders presence but some information regarding electromagnetic velocity could be extracted. These results strongly suggest that such landforms contain ice, are therefore important to include in future inventories and should be considered when evaluating the hydrological importance of a particular region.</p><p> </p>

scholarly journals Integrated Study of Geotechnical and Geophysical Methods to Assess the Soil Corrosion Potential for Construction Site

2020 ◽  
Vol 11 (3) ◽  
pp. 79-85
Author(s):  
Perveiz Khalid ◽  
Shahzada Khurram ◽  
Zia Ud Din ◽  
Syed Atif Ali ◽  
Alabjah Bahija
Keyword(s):  
Electrical Resistivity ◽  
Corrosion Potential ◽  
Geophysical Methods ◽  
Steel Structures ◽  
Critical Issue ◽  
Silty Clay ◽  
Soil System ◽  
Near Surface ◽  
Soil Corrosion ◽  
Electrical Resistivity Survey

Corrosion of subsurface steel structures is very critical issue especially in moisture subsoil. The use ofphysiochemical properties such as pH, salts concentration, electrical resistivity is very common to quantify corrosivenature of subsoil. However, the laboratory measurements of these parameters are quite difficult due to time and budgetconstraints. In this work soil corrosion potential of a power plant site was evaluated using geophysical and geotechnicalinvestigations. Soil samples were collected from 15 boreholes drilled up-to 50 m depth for laboratory testing whereas 3probes of four electrodes vertical electrical sounding (VES) using Wenner configuration were also performed tomeasure the electrical resistivity of the subsurface soil up to 50 m depth. According to the USCS soil system silty clay(CL-ML) was interpreted as dominant material in all boreholes as shallow depth. Poorly graded sand (SP) including silt(SM) was found of variable depth in almost each borehole. The true resistivity values at the depth of 30 meters liesbetween the 19.9 ohm- meters to 59.8 ohm meters. All observation points of electrical resistivity survey VES-I, VES-IIand VES-III near-surface material show moderate soil corrosion potential which is favorable for design of earthing. Upto depth of 4 m, the values of resistivity 52.6 to 59.8 ohm-meters shows adequate estimation of corrosion. According tothe International standard these curves belong to bell type or K type curve of resistivity model. Their resistivity valueswith respect to depth show low to moderate corrosion potential which is satisfactory for construction at this depth afterapplying the nominal cathodic protections. Thus, electric pipe lines may be installed at this depth.

scholarly journals Subsurface Investigation Using Electrical Resistivity Imaging for Proposed Industrial Site near Erbil-Kirkuk Borders, Northern Iraq

2021 ◽  
Vol 54 (2E) ◽  
pp. 198-209
Author(s):  
Osamah Al-Saadi
Keyword(s):  
Electrical Resistivity ◽  
Geophysical Methods ◽  
Electrode Spacing ◽  
Electrical Resistivity Imaging ◽  
Industrial Site ◽  
Near Surface ◽  
Running Water ◽  
Resistivity Imaging ◽  
Clastic Rocks ◽  
Industry Area

The friendly-environment geophysical methods are commonly used in various engineering and near-surface environmental investigations. Electrical Resistivity Imaging technique was used to investigate the subsurface rocks, sediments properties of a proposed industrial site to characterize the lateral and vertical lithological changes. via the electrical resistivity, to give an overview about the karst, weak and robust subsoil zones. Nineteen 2D ERI profiles using Wenner array with 2 m electrode spacing have been applied to investigate the specific industry area. One of these profiles has been conducted with one-meter electrode spacing. The surveyed profiles are divided into a number of blocks, each block consists of several parallel profiles in a specific direction. The positions of Electrical Resistivity Imaging profiles in the project area have been determined according to a preliminary subject plan from the civil engineers for factory foundation constructions and proposed locations of heavy machines. The inversion results of profiles showed that areas of blocks A, B, C, and D consist mainly of clastic rocks and sediments, e.g., claystone, siltstone and sandstone. The Electrical Resistivity Imaging inversion sections of blocks A, B, C, and D do not show any indication of cavitation or weak zones of sizes more than 2.0 meters, and no signs of gypsum bodies are found in these areas in general. Gypsum bodies are probably detected at block E, the southern part of the study area. The researchers recommended to keep these rocks in block E away from the continuous running water to avoid cavitation. Furthermore, the construction of heavy machines should keep away from this part of the study area to avoid to some extent, subsoil failure and subsidence in the future. Middle and Northern parts are more consistent to the constructions and factory foundations.

scholarly journals Mapping the Distribution of Buried Glacier Ice – An Example From Lago Delle Locce, Monte Rosa, Italian Alps

1986 ◽  
Vol 8 ◽  
pp. 78-81 ◽  
Author(s):  
W. Haeberli ◽  
F. Epifani
Keyword(s):  
Snow Cover ◽  
Seismic Refraction ◽  
Italian Alps ◽  
Frozen Ground ◽  
Near Surface ◽  
Winter Snow ◽  
Glacier Ice ◽  
Geoelectrical Resistivity ◽  
Monte Rosa

Techniques for mapping the distribution of buried glacier ice are discussed and the results, from a study carried out within the framework of flood protection work in the Italian Alps, are presented. Bottom temperatures of the winter snow cover (BTS) primarily indicate the heat flow conditions in the underlying ground and mainly depend on the presence or absence of an ice layer beneath the surface. Determination of BTS values is therefore an inexpensive method for quickly mapping the near-surface underground ice in areas where there is 1 m or more of winter snow cover. At greater depths, and/or when more detail is required, geoelectrical resistivity soundings and seismic refraction soundings are most commonly used to investigate underground ice. A combination of the two sounding techniques allows the vertical extent and the main characteristics (frozen ground, dead glacier ice) to be determined in at least a semi-quantitative way. Complications mainly arise from irregularity in the horizontal extension of the studied underground ice bodies, and they may have to be overcome by expensive core drillings and borehole measurements. Widespread occurrence of buried glacier ice was observed in morainic deposits, surrounding an ice-dammed lake near Macugnaga, Italy.

Efficiency Of Integrated Seismic Methods Approach To Near-Surface Characterization

2020 ◽  
Author(s):  
Irena Gjorgjeska ◽  
Vlatko Sheshov ◽  
Kemal Edip ◽  
Dragi Dojchinovski
Keyword(s):  
Surface Characterization ◽  
Seismic Refraction ◽  
Geophysical Methods ◽  
Cost Effective ◽  
Integrated Approach ◽  
Image Resolution ◽  
Future Research ◽  
Near Surface ◽  
Seismic Methods ◽  
Refraction Seismic

<p>Surface seismic methods are among the most popular, widely accepted, geophysical methods for near-surface characterization. The most practical and effective way to perform in-situ measurements and data processing using different seismic methods as are seismic refraction, seismic reflection and MASW method in an integrated approach is presented in this paper. Each method has some advantages and limitations, but their application in an integrated approach provides higher accuracy in subsurface modeling. The same seismic equipment and, in most of the cases, the same acquisition parameters were used, enabling time and cost effective survey for subsurface characterization. The choice of these parameters was not random. Experimental research by use of the above-mentioned seismic methods was carried out in a long period in order to define the optimal parameters for successful application of an integrated technique in future research. During this survey, particular attention was paid to the influence of the acquisition parameters on the dispersion image resolution in the MASW surveys and extraction of an effective dispersion curve.</p><p>The results of the performed surveys at characteristic locations in R. North Macedonia are presented to show the efficiency of the combined methods approach.</p>

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