Rapid, non-intrusive geophysical methods for assessing dikes in urban areas—conclusions from the FloodProBE geophysics workshop

2012 ◽  
Author(s):  
C Fauchard ◽  
S Lopes ◽  
M Morris ◽  
J Simm ◽  
P Royet
Keyword(s):  
Urban Areas ◽  
Geophysical Methods

Application of geophysical methods to evaluate hydrology and soil properties in urban areas

Urban Water ◽  
2001 ◽  
Vol 3 (3) ◽  
pp. 205-216 ◽  
Author(s):  
Larisa Pozdnyakova ◽  
Anatoly Pozdnyakov ◽  
Renduo Zhang
Keyword(s):  
Soil Properties ◽  
Urban Areas ◽  
Geophysical Methods

scholarly journals Application of Cross-Hole Tomography for Assessment of Soil Stabilization by Grout Injection

Geosciences ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 399 ◽  
Author(s):  
Mikhail Lebedev ◽  
Kirill Dorokhin
Keyword(s):  
Seismic Tomography ◽  
Urban Areas ◽  
Soil Stabilization ◽  
Geophysical Methods ◽  
Negative Influence ◽  
Actual State ◽  
Existing Buildings ◽  
Practical Applications ◽  
Geotechnical Monitoring ◽  
Urban Conditions

Currently, the spread of megalopolises poses an ever-increasing necessity for underground space development for the purpose of the arrangement of transport communications, underground parking areas, trade areas, etc. The implementation of such projects entails a significant increase in the risk of accidents and damage to existing buildings within construction activity influence areas. The reduction of the risk of accidents during the construction of underground facilities within urban areas may only become possible with the identification of adverse factors negatively influencing existing buildings or a facility under erection and elaboration (to reduce such negative influence). The application of geophysical methods in complex assessments of the actual state of an encompassing mass significantly increases efficiency and the credibility of geotechnical monitoring. The application of seismic tomography significantly increases the resolution capability of surveys. Existing techniques, e.g., seismic tomography, allow for any depths to be investigated at a high resolution, even given constricted urban conditions. This article covers the practical applications of seismic tomography in qualitative assessments of actions and an efficiency evaluation of the injective stabilization of soil.

scholarly journals Detection of Underground Anomalies Using Analysis of Ground Penetrating Radar Attribute

2020 ◽  
Vol 1 (1) ◽  
Author(s):  
Cuong Van Anh LE ◽  
Thuan Van NGUYEN
Keyword(s):  
Ground Penetrating Radar ◽  
Urban Areas ◽  
Geophysical Methods ◽  
Synthetic Data ◽  
Drainage System ◽  
Real Data ◽  
Building Structures ◽  
Water Drainage ◽  
Diffraction Curve ◽  
Ground Penetrating

Need of specifying underground construction works for supporting further tasks as maintenance, repairing, or setting up new underground structures. For these needs, ground penetrating radar, one of the efficient geophysical methods, can bring high-resolution and quick underground image revealing existence of both natural and artificial anomalies. Its fixed receiver-transmitter antennas setting as constant offset is commonly used in urban areas. Conventionally, hyperbolae events are crucial indicator for scattering objects as kinds of pipes, water drainage system, and concrete building structures as well as sink holes. Calculation of their depths and sizes requires migration analysis with the environment velocity. Migrated sections with different velocity show different chaos degrees of transformation from a hyperbola diffraction curve to its focused area. We have researched diagrams of different Ground Penetrating Radar attributes as energy, entropy, and varimax dependent on two variables, velocity and window zone covering diffraction events from a set of synthetic data and real data, in specifying the environment velocity. We have developed a novel technique for evaluation of the ground velocity and object’s size by combination of the new varimax diagram and the Kirchhoff migration method. The technique can define contribution of diffracted ground penetrating radar waves for building the diagram after removing the reflection contribution. The synthetic datasets consist of different random background noise levels and expressions of different-sized circular and rectangular pipes. The real data is measured for detecting two underground gas pipes in Ba Ria – Vung Tau province, Vietnam.

scholarly journals Geophysical prospecting in the Doukkala area (Swalah commune) in Morocco

2020 ◽  
Vol 150 ◽  
pp. 03008
Author(s):  
Halima Soussi ◽  
Lahcen Bahi ◽  
Latifa Ouadif ◽  
Mohamed Chibout ◽  
Brahim Aghazzaf ◽  
...  
Keyword(s):  
Rural Areas ◽  
Urban Areas ◽  
Geophysical Methods ◽  
Economic Consequences ◽  
Vertical Electrical Soundings ◽  
Damage Costs ◽  
Electrical Soundings ◽  
Urban And Rural Areas ◽  
El Jadida ◽  
Very High

The collapse of the subsoil creates a risk for the population whether it is urban or rural. Each year, the damage caused by these collapses has considerable socio-economic consequences, and the damage costs are very high. Thus, the detection of these areas of collapse in urban and rural areas is important to prevent and avoid socio-economic consequences, and to establish a preventive risk planning to have a better protection of people and goods. The commune of Swalah, study area, belongs to the province of El Jadida which is part of those areas of Doukkala exposed to the risk of collapse due to the presence of underground cavities. These cavities are potentially dangerous for humans, especially in urban areas. They have different extensions that can be caused by natural or anthropic origin. Their size, as well as the physical properties of the external environment in which they are located, allow the use of different geophysical methods. The use of these geophysical methods is the best to detect and delineate cavities in this region. The present study was based on a geophysical compaign of vertical electrical soundings. Indeed, 50 electrical soundings were modeled and reinterpreted and allowed to detect and delineate any potential cavities in the region.

scholarly journals Evaluating the Geotechnical and Geophysical Characteristics of Expanding Districts in Tehran Using Field Experiments

2018 ◽  
Vol 4 (2) ◽  
pp. 363
Author(s):  
Arash Razmyar ◽  
Abolfazl Eslami
Keyword(s):  
Urban Areas ◽  
Field Experiments ◽  
Geophysical Methods ◽  
Field Tests ◽  
Young Modulus ◽  
Friction Angle ◽  
Standard Penetration Test ◽  
Penetration Test ◽  
Engineering Structures ◽  
Geotechnical Characteristics

Considering the increasing population growth and the rapid growth of urbanization and pollution in the environment, providing zoning maps and urban engineering geology seem to be important. The rapid construction growth of cities, as well as the confrontation with events such as earthquakes and failure to observe the geological and geotechnical issues, has caused many engineering problems. The use of geophysical methods not only cannot lonely provide us a complete and comprehensive information on the geotechnical conditions of the earth but also has many disturbances in urban areas, and its use in urban centers is almost impractical. Therefore, it seems that the best way of examining and interpreting the geotechnical characteristics of a site, especially in urban areas, is the use of suspicious data. Therefore, performing geotechnical studies and geotechnical zoning can be useful for retrofitting buildings and engineering structures and reducing their risks. Hence, zoning studies are conducted in this research in order to better recognize the technical soil status for safe construction due to rising the population of Tehran in recent decades and the concentration of population in certain areas of Tehran, especially in the eastern and western regions (districts 4 and 22). In this study, different geotechnical field tests such as standard penetration test (SPT), cone penetration test (CPT) were used to estimate parameters such as adhesion coefficient (C), internal friction angle ( ), Young modulus (E). Other common experiments with conventional geophysical experiments, such as in good experiments, refractive and CSSW were applied to estimate geophysical parameters of bedrock depth and shear wave velocity for zoning these areas.

2D INVERSION OF DIPOLE-DIPOLE AXIAL ARRAY WITH LINEAR CAPACITIVE ELECTRODES FOR ENGINEERING TASKS

2019 ◽  
Vol 13 (2) ◽  
pp. 60-68
Author(s):  
A. Yu. Tatarskiy ◽  
A. F. Volynin
Keyword(s):  
Urban Areas ◽  
Geophysical Methods ◽  
Electrode Array ◽  
Field Work ◽  
Geological Structure ◽  
Industrial Facilities ◽  
Data Inversion ◽  
2D Data ◽  
High Level ◽  
2D Resistivity

Abstract: at present, the range of tasks solved by geophysical methods is expanding. This is facilitated by the progress in the development of geophysical equipment, methods for performing field work and data processing. At the same time, the conditions of research are complicated. Often it is the site of industrial facilities or urban areas. The main factors complicating the implementation of the geophysical researches at urban areas are the high level of industrial noise and solid coverage. The article discusses the possibility of using resistance technology with 2D data inversion when solving engineering problems in urban areas. The conditions of the use of the measurement technique with capacitive electrodes for approximation by grounded electrode array at a direct current are shown. The results of the comparison of the dipole-dipole method with capacitive electrode array and its equivalent with galvanic grounded electrodes are presented. To assess the effectiveness of using of the capacitive electrodes array for solving engineering tasks in the city, the authors carried out researches on a site of regularly emerging subsidence of pavement in the center of St. Petersburg. According to the research results, a 2D resistivity section of the pavement deformation was constructed. The results were interpreted using geological information. The studies revealed a spatial correlation of the identified anomalies of specific electrical resistances with the local site of the embankment pavement destruction. The possible causes of the identified anomalies are described. The results of electrical prospecting with linear capacitive electrodes can be used for detailing engineering geological structure of urbanized areas.

USING SEISMOACOUSTIC METHODS IN KARST TERRITORIES OF LARGE CITIES (A CASE STUDY OF MOSCOW AND NIZHNY NOVGOROD)

2019 ◽  
Vol 12 (9-10) ◽  
pp. 50-62
Author(s):  
A. D. Kochev ◽  
L. G. Chertkov
Keyword(s):  
Urban Areas ◽  
Survey Methods ◽  
Geophysical Methods ◽  
Seismic Survey ◽  
Low Velocity ◽  
Borehole Geophysics ◽  
Large Cities ◽  
Common Depth Point ◽  
Coal Deposits ◽  
Seismic Vibrations

Various geophysical methods are used to study the karst of carbonate massifs, the effectiveness of which in the conditions of large cities is low, since they are affected by intense industrial and transport disturbances. The paper discusses the use of seismic acoustic methods of ground and borehole geophysics: the method of the common depth point (CDP), the method of refracted waves (MRW), crosswell seismoacoustic sounding (CSS). It is shown that seismic survey methods provide more informative engineering-geological research. The use of a non-explosive source of excitation of seismic vibrations made it possible to carry out research in urban areas. As a result of the implementation of a system for accumulating useful seismic signals, informative material was obtained in areas of intense industrial interference. The resolution of seismic surveys on the mapping of coal deposits and the construction of maps of the paleorelief is clearly visible from a comparison of geological maps constructed from drilling data and taking seismic studies into account. In combination with crosshole seismic acoustic sounding, it is possible to fix relatively large karst cavities and destroyed zones. Complicating in the interpretation of seismoacoustic indicators is the fact that the carbonate massif is often a relatively evenly karsted system in the form of karst cavities of various sizes (mostly irregular in shape, filled or open), fracturing, cavernosity and porosity. As a result, the motley pattern of the distribution of the velocities of elastic waves is averaged, making it difficult to isolate low-velocity zones confined to karst cavities. Additionally, according to the data of microseismic logging — vertical seismic profiling (MSL — VSP), it is possible to identify low-speed zones associated with decompaction in the upper cover layer of rocks, from which sandy sediments are transported to a carbonate strongly karsted massif. Seismoacoustic sounding allows you to control the quality of grouting works when filling karst cavities with cement mortar.

scholarly journals Distributed Acoustic Sensing from mHz to kHz: Empirical Investigations of DAS Instrument Response

2020 ◽  
Author(s):  
Patrick Paitz ◽  
Pascal Edme ◽  
Cédric Schmelzbach ◽  
Joesph Doetsch ◽  
Dominik Gräff ◽  
...  
Keyword(s):  
Urban Areas ◽  
Waveform Inversion ◽  
Geophysical Methods ◽  
Low Frequency ◽  
Acoustic Sensing ◽  
Temporal Sampling ◽  
Cable Properties ◽  
Instrument Response ◽  
Distributed Acoustic Sensing ◽  
Initial Results

<p>With the upside of high spatial and temporal sampling even in remote or urban areas using existing fiber-optic infrastructure, Distributed Acoustic Sensing (DAS) is in the process of revolutionising the way we look at seismological data acquisition. However, recent publications show variations of the quality of DAS measurements along a single cable. In addition to site- and orientation effects, data quality is strongly affected by the transfer function between the deforming medium and the fiber, which in turn depends on the fiber-ground coupling and the cable properties. Analyses of the DAS instrument response functions in a limited part of the seismological frequency band are typically based on comparisons with well-coupled conventional seismometers for which the instrument response is sufficiently well known to be removed from the signal.</p><p>In this study, we extend the common narrow-band analyses to DAS response analyses covering a frequency range of five orders of magnitude ranging from ~4000 s period to frequencies up to ~100 Hz. This is based on a series of experiments in Switzerland, including (1) active controlled-source experiments with co-located seismometers and geophones, (2) low-frequency strain induced by hydraulic injection in a borehole with co-located Fiber-Bragg-Grating (FBG) strain-meters, and (3) local to teleseismic ice- and earthquake recordings with  co-located broadband stations.</p><p>Initial results show a site-unspecific, approximately flat instrument response for all experiments.</p><p>The initial results suggest that the amplitude and phase information of DAS recordings are sufficient for conventional geophysical methods such as event localisation, full-waveform inversion, ambient noise tomography and even event magnitude estimation. Despite the promising initial results, further engagement by the DAS community is required to evaluate the DAS performance and repeatability among different interrogation units and study sites.</p>

Shear Wave Velocity Analysis of 2-D Multichannel Analysis of Surface Wave (MASW) to investigate subsurface Fault of Alternative Bridge Construction in Kelok Sago Jambi

2020 ◽  
Vol 25 (1) ◽  
pp. 18-20
Author(s):  
Muhammad Farhan ◽  
◽  
Gunawan Handayani ◽  
Keyword(s):  
Surface Wave ◽  
Surface Waves ◽  
Wave Velocity ◽  
Urban Areas ◽  
Signal To Noise Ratio ◽  
Body Wave ◽  
Geophysical Methods ◽  
P Wave ◽  
S Wave ◽  
Multichannel Analysis

Every geotechnical measurement requires geophysical methods to classify soil types under the ground. S-wave velocity (Vs), P-wave velocity (Vp), and density (ρ), are the most important parameters in the classification of soils. There are various methods to determine Vs, one of them is P-S logging method. However, this method is less suitable to be applied in urban areas due to the difficulties of data acquisition and high expense in operational costs. In 1999, a seismic method uses surface waves to de-termine Vs profile with a higher signal to noise ratio which was known by the name of Multichannel Analysis of Surface Waves (MASW). A surface wave, especially Rayleigh wave, creeps slowly on the surface with a larger amplitude than a body wave. The wavelengths of the surface wave will disperse in the layers system i.e. the phase velocity of the surface waves is now func-tion of frequency. MASW 2-D method is used in this paper to determine subsoil properties and to identify the fault under the bridge abutments plan (abutment 1 and abutment 2) in Kelok Sago Jambi.

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