Documents published in Scipedia

• MASW Joint Analysis of Rayleigh and Love Waves for Site Characterization

  J. Hellín-Rodríguez, P. Martínez-Pagán*, I. Valverde-Palacios, A. García-Jerez, K. Suto, M. Martínez-Segura, J. Orta, J. Álvarez-Lozano

  ISC2024.

  
  

  Abstract

  The determination of reliable shear-wave velocity models using Multichannel Analysis of Surface Waves (MASW) has increased importantly for site characterisation studies due to their use in geotechnical studies and regulations. The standard MASW approach is commonly based on the analysis of vertical component of Rayleigh waves, which can result in inaccurate and potentially erroneous interpretations by personal bias. Thus, we present the joint analysis of different and independent multi-component data based on Rayleigh and Love waves to obtain 2D Vs sections for site characterization. Those seismic data were recorded using a landstreamer consisting of 8 triaxial 4.5Hz geophones. To generate Rayleigh waves, the blows were given vertically on a plate, and for the Love waves the blows were given laterally on a horizontal wooden beam. A joint analysis of Rayleigh and Love waves data was conducted on seismic data recorded from the metropolitan area of Granada city (Spain) to generate their dispersion curves. This new approach enabled a proper identification of fundamental- and higher-mode surface waves facilitating the reliable reconstruction of subsurface Vs profiles through a robust joint inversion process. The MASW 1D Vs versus depth models were corroborated at several test sites by the information obtained from boreholes. Thus, the main geological formations could be inferred from MASW 2D Vs sections down to a depth of 30 meters, as well as the Vs30 parameter to perform a reliable seismic microzonation of the study area. This methodology provides a very well constrained inversion procedure capable of providing a robust subsurface Vs model for site characterization.

  Abstract
  The determination of reliable shear-wave velocity models using Multichannel Analysis of Surface Waves (MASW) has increased importantly for site characterisation studies due [...]

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• Classification of an Exposed Mixed-Sediment Tidal Flat Using Synthetic Aperture Radar

  J. Paprocki*, N. Stark, F. Falcone, H. Graber

  ISC2024.

  
  

  Abstract

  Estuarine tidal flats represent a critical environment for maintaining healthy ecosystems. The geotechnical characterization of such environments is often challenging due to their soft nature and remote locations. Thus, the goal of this study is to explore the use of remotely sensed, high resolution (pixel resolution of ~0.5 m) synthetic aperture radar (SAR) data for characterizing these sediments. Towards this goal, the variability of sediment properties (median gain size, moisture content, fines content, and classification following the Unified Soil Classification System (USCS) were documented for a mixed tidal flat located on the Great Bay Esturay in New Hampshire, USA. A sediment classification scheme based on SAR, originally proposed by Gade et al. (2008), which utilizes the correlation length to characterize sediments based on the percentage of particles

  Abstract
  Estuarine tidal flats represent a critical environment for maintaining healthy ecosystems. The geotechnical characterization of such environments is often challenging due [...]

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• 3D Resistivity Survey of a Weathering Profile of Metamorphic Rocks in State of Pernambuco, Brazil

  R. Coutinho*, C. Bortolozo, M. Andrade, F. Silva

  ISC2024.

  
  

  Abstract

  This paper aims to study a weathering profile of crystalline rocks in the City of Camaragibe, State of Pernambuco, Brazil. For this purpose, a survey using electroresistivity was conducted. A regular mesh was performed aiming at 3D acquisition. The target area of the survey has 3 meters of depth (the Data Collection Platform, abbreviated as PCD) responsible for recording soil moisture information. An auger soil sampler was also made reaching a depth of 3 meters to describe and identify the substrate. The main objectives of the paper are to determine the geoelectrical characteristics of the materials and relate them to the strata previously identified and the soil moisture profiles. A goal was also to calculate moisture from the resistivity model and compare the results with those obtained by the PCD. The results allowed the creation of 3D geo-electric models, extending to a depth of 8 meters. It was also possible to create a 3D soil moisture model. It was possible to make a correlation between the geoelectric horizons and the layers of the rock alteration profile. The humidity results obtained by PCD and the resistivity model were examined, indicating favorable prospects for applying the method.

  Abstract
  This paper aims to study a weathering profile of crystalline rocks in the City of Camaragibe, State of Pernambuco, Brazil. For this purpose, a survey using electroresistivity [...]

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• Muon Tomography for Mapping and Monitoring Tailings Storage Facilities

  M. McLean, F. Scutti, R. Seikel, S. Krishnan, C. Webster, S. Collins, C. Goss, S. Palanisamy, P. Panchal, J. Donovan, A. Duffy, A. Christensen*

  ISC2024.

  
  

  Abstract

  Tailings storage facilities pose an increasingly significant global challenge for mining companies. Given that tailings, the by-products of mine processing plants, demand meticulous management due to the potential hazards associated with storage facility failures, continuous attention is imperative. The repercussions of such incidents can lead to profound and enduring environmental damage in downstream regions. Therefore, consistently monitoring the structural stability of these facilities is paramount to ensure the safety and sustainability of both active mining sites and legacy mines. This paper introduces an innovative approach using muon tomography to analyze the internal density structures of tailings dams. The research, conducted at the BHP Prominent Hill Mine site in South Australia, presents a pioneering method and technology for examining the internal density distribution of tailings storage facilities using muons. Muons, being a natural source of radiation capable of generating X-ray-like scans of large structures, offer a distinctive opportunity to gain insights into the inner structure of tailings storage facilities. Moreover, this technology holds the potential to serve as a foundational platform for future research in the development of early warning systems for detecting structural changes.

  Abstract
  Tailings storage facilities pose an increasingly significant global challenge for mining companies. Given that tailings, the by-products of mine processing plants, demand [...]

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• Site Characterization with Surface Waves in Kazakhstan

  S. Abdialimi, D. Tuzelbayev, J. Kim, Y. Shokbarov, T. Ku, S. Moon*, V. Khomyakov

  ISC2024.

  
  

  Abstract

  The South and Southeast Kazakhstan regions exhibit notable seismicity due to intricate tectonic interactions, albeit experiencing infrequent catastrophic earthquakes. Proximate to the convergence of the Eurasian and Indian plates, this region witnesses frequent seismic activity, particularly in cities like Almaty near mountainous terrain. Given the significant seismic activity, comprehensive site characterization is imperative. Traditionally, evaluating dynamic soil properties relies on conventional borehole logging techniques. However, the emergence of the multi-channel analysis of surface waves (MASW) offers advantages in cost, time efficiency, and non-invasiveness. Despite its benefits, MASW remains underutilized in Kazakhstan and is absent from local building codes, unlike neighboring CIS countries. This study aims to demonstrate the applicability of the MASW method for site characterization in Kazakhstan's seismic regions. Through extensive work, shear wave velocity (𝑉𝑠) values were estimated and compared with reference data obtained from seismic refraction and dilatometer testing. The results showed significant agreement, highlighting the suitability and effectiveness of the MASW method in Kazakhstan.

  Abstract
  The South and Southeast Kazakhstan regions exhibit notable seismicity due to intricate tectonic interactions, albeit experiencing infrequent catastrophic earthquakes. Proximate [...]

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• Identification of density of earth-fill dam using muography

  T. Shibata*, K. Takahashi, S. Nishimura, T. Shuku

  ISC2024.

  
  

  Abstract

  In recent years, the high probability of large-scale earthquakes occurring in Japan has become a major social concern; and thus, it is urgent that countermeasures and maintenance be implemented for the protection of large-scale societal infrastructures from damage due to these earthquakes. When large-scale societal infrastructures are inspected, an internal diagnosis is required to evaluate the damage condition of the structures in order to see what countermeasures should be planned ahead of the occurrence of any earthquakes. However, conventional methods of diagnosis, such as groundpenetrating radar, have their limitations. Namely, they provide high-precision results in shallow areas, but results with reduced resolution in deeper regions. To overcome the shortcomings associated with these conventional methods of exploring depths out of the investigation range, one approach is to use muography1). This paper investigates the applicability of muon exploration techniques, using cosmic-ray muons, to probe the density of structures inside earth-fill dams.

  Abstract
  In recent years, the high probability of large-scale earthquakes occurring in Japan has become a major social concern; and thus, it is urgent that countermeasures and maintenance [...]

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• Comprehensive geometric characterization of the subsurface using Microseismic Resonance: identifying sinkholes by modelling the bedrock surface and karstic features in a challenging environment

  M. Green*, M. Jessop, P. Pires

  ISC2024.

  
  

  Abstract

  This study presents a comprehensive assessment of the subsurface characteristics at a Unigel processing facility in Pedra Blanca, Sergipe, Brazil, utilizing Microseismic Resonance (MSR). The facility experienced the emergence of sinkholes and depressional features near critical infrastructure, prompting the need for a thorough subsurface characterization. MSR, a burgeoning microseismic technique, was employed due to its ability to geometrically characterize subsurface structures without the limitations of large geophone arrays. Fieldwork involved MSR data collection on a 10m by 10m grid over a 37.14 hectare area, complemented by borehole data and a gravity survey. Results revealed the intricacies of complex stratigraphy with Quaternary fluvial deposits overlying Early Cretaceous carbonates with karstic morphology. MSR data processing produced a holistic geometric model of the subsurface, including the identification of karstic features. Comparison with borehole data demonstrated high accuracy, with MSR Local Component (LC) data rendering a bedrock surface of approximately 99% accuracy. MSR Full Spectrum data (FS) is correlated with the gravity study validating the presence of karstic structures. This study showcases MSR as a powerful, non-invasive tool for rapid and accurate subsurface characterization, crucial for infrastructure security and environmental assessment

  Abstract
  This study presents a comprehensive assessment of the subsurface characteristics at a Unigel processing facility in Pedra Blanca, Sergipe, Brazil, utilizing Microseismic Resonance [...]

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• Seismic Interferometry Technique for Characterization of Loose Soil Layers

  S. Gokyer Erbis*, W. Marr, T. Bardainne, R. Tarnus

  ISC2024.

  
  

  Abstract

  Surface wave tomography is a feasible method to provide complementary data to better understand the continuity of soil strata. It may also be used to determine best locations for invasive testing. Surface wave tomography methods are frequently used to delineate soil-rock interface and determine average shear wave velocity for seismic site class determination. Delineation within the soils layers where the change in seismic velocity within the soil layers are relatively small requires higher resolution data collection and enhanced processing methods than those used historically in surface wave tomography. This study uses a patented imaging and monitoring system based on the passive seismic interferometry technique augmented by active seismic sources at known locations. A dense nodal array of MEMs accelerometers were deployed at a site where known saturated loose materials exist. This paper presents shear wave velocity (Vs) data deduced from surface wave measurements where various, compression wave velocity (Vp) to Vs ratios were considered, especially showing the effect of Vp/Vs ratio, on the Vs data. This ratio which was traditionally assumed can have a significant effect on the inferred Vs. This paper also presents the comparison of deduced Vs data to measured Vs data by seismic cone penetration test and makes some recommendations for how to improve the methods to determine shear wave velocity in soft/loose soils.

  Abstract
  Surface wave tomography is a feasible method to provide complementary data to better understand the continuity of soil strata. It may also be used to determine best locations [...]

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• Critical Speed of Railway Rections Obtained Using Surface Wave Analysis Tests

  Á. Tijera*, R. Ruiz, J. Estaire

  ISC2024.

  
  

  Abstract

  In recent years, there has been a global trend towards increasing the commercial speed of high-speed rail lines (HSLs) to cope with expected demand problems. Examples include the new HSLs projects for the UK and California, where the design speed reaches 400 km/h. Therefore, one of the biggest challenges currently faced by the railway sector is the determination of the critical speed value of railway sections. This is true both for future HSLs, due to their high design speeds, and for existing rail lines, due to the intended increase in commercial speed. The critical speed is that train speed that produces a dynamic amplification in the medium underlying the track, causing an amplification of the vertical movement of the track components and the supporting ground such that the stability of the infrastructure and the safety of passengers is compromised. This work sets out the methodology necessary to experimentally study the critical speed of a railway section by in situ applying surface wave spectral analysis techniques, SASW and MASW. The critical speed is determined by the lowest phase velocity of the local minima of the modal dispersion curves, or by the minimum of the apparent dispersion curve. Both methods are equivalent. This paper also presents the results obtained on some Spanish HSLs, both on tracks under construction and in operation. In the cases studied, the ballast layer is the one that presents the lowest shear wave velocity and the minimum of the dispersion curve, so it is the layer that determines the critical speed.

  Abstract
  In recent years, there has been a global trend towards increasing the commercial speed of high-speed rail lines (HSLs) to cope with expected demand problems. Examples include [...]

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• Collapse Risk Evaluation of Subsurface Cavities in Pavements of Full-Scale Test Roads

  R. Kuwano*, J. Kuwano, Y. Karasaki, R. Sera, T. Ihara

  ISC2024.

  
  

  Abstract

  In order to solve the problem of subsurface cavities in urban areas, industry, government and academia carried out collaborative research over 2018-2020. In this joint research, analysis of existing cavity data, laboratory model experiments, numerical analysis, and full-scale field test, monitoring of the cavity in the road, etc. were conducted. In this study, a full-scale test road was constructed with artificial cavities installed to evaluate the risk of collapse in consideration of the road structure. A series of plate loading tests and falling weight deflectometer tests was conducted on the road surface above a cavity to understand the cavity behaviour. A surface wave survey was also conducted to evaluate the wave propagation on and around cavities. It was found to be reasonable to evaluate the collapse risk of subsurface cavities by the ratio of depth and width of cavities, in which the thickness of the pavement should be excluded from the depth.

  Abstract
  In order to solve the problem of subsurface cavities in urban areas, industry, government and academia carried out collaborative research over 2018-2020. In this joint research, [...]

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