Application of Linear-Array Microtremor Surveys for Rock Mass Classification in Urban Tunnel Design

Ho, Young; Kang, Jong Suk; Jo, Churl-Hyun

doi:10.1071/eg06108

Cited by 14 publications

(3 citation statements)

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“…Apart from radar imaging, seismic methods play a more and more important role in characterizing rock sites for geotechnical purpose. As an example, a relationship between shear wave velocity and the Rock Mass Rating, which is a geotechnical factor used for tunnel design, was recently proposed by Cha et al [2006]. In landslide investigation, similar relation ships, linking for instance geophysical parameters to the displacement rate should be studied more deeply About assessing hydrogeological properties from geophysical data, outstanding results have been obtained in recent years in a new interdisciplinary field (hydrogeophysics), combining the integration of multiple sources of data and the development of comprehensive petrophysical models.…”

Section: Discussionmentioning

confidence: 99%

Geophysical investigation of landslides : a review

Jongmans

Garambois

2007

Bulletin De La Société Géologique De France

322

176

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Abstract. -In the last two decades, shallow geophysics has considerably evolved with the emergence of 2D spatial imaging, then 3D spatial imaging and now 4D time and space imaging. These techniques allow the study of the spatial and temporal variations of geological structures. This paper aims at presenting a current state-of-the-art on the application of surface geophysical methods to landslide characterization and focuses on recent papers (after 1990) published in peer-reviewed International Journals. Until recently, geophysical techniques have been relatively little used for the reconnaissance of landslides for at least two main reasons. The first one is that geophysical methods provide images in terms of physical parameters which are not directly linked to the geological and mechanical properties required by geologists and engineers. The second reason shown through this study probably comes from a tendency among a part of the geophysicists to overestimate the quality and reliability of the results. This paper gave the opportunity to review recent applications of the main geophysical techniques to landslide characterisation, showing both their interest and their limits. We also emphasized the geophysical image characteristics (resolution, penetration depth) which have to be provided for assessing their reliability, as well as the absolute requirements to combine geophysical methods and to calibrate them with existing geological and geotechnical data. We hope that this paper will contribute to fill the gaps between communities and to strength of using appropriate geophysical methods for landslide investigation. Reconnaissance géophysique des glissements de terrain : Etat de l'artMots clés. -Glissements de terrain, Investigations géophysiques, Etat de l'art Résumé. -Depuis 20 ans, la prospection géophysique à faible profondeur a considérablement évolué avec l'apparition de techniques d'imagerie 2D (x,z), puis 3D (x,y,z) et maintenant 4D (x,y,z,t), qui permettent de considérer les variations spatiales et temporelles des objets géologiques étudiés. A partir de la littérature internationale, nous tentons de faire une synthèse sur l'application des méthodes géophysiques à l'étude et au suivi des mouvements de terrain qui sont des structures complexes et évolutives. Paradoxalement, il apparaît que l'utilisation des techniques géophysiques pour la reconnaissance des mouvements de terrain est restée jusque récemment relativement limitée pour deux raisons principales. La première vient de la réticence d'une partie des ingénieurs et des géologues d'appliquer des techniques complexes qui ne fournissent pas des données géologiques, hydrogéologiques ou mécaniques directement utilisables. La seconde raison, apparue lors de cette étude, résulte de la tendance d'une partie de la communauté géophysique de surestimer la qualité et la fiabilité des résultats obtenus. A travers cette synthèse des publications, nous passons en revue les applications récentes des principales méthodes géophysiques aux mouvements de terrain en illust...

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Section: Discussionmentioning

confidence: 99%

Geophysical investigation of landslides : a review

Jongmans

Garambois

2007

Bulletin De La Société Géologique De France

322

176

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“…This model was changed later for seismic analysis in other regions later (Barton 1995(Barton , 2007. Cha et al (2006) and Zafirovski et al (2012) investigated the relationship between the RMR and the pressure and shear wave velocity near the earth's surface. However, very few studies are done on the relationship between the RMR and the seismic wave velocity.…”

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confidence: 99%

Classification and assessment of rock mass parameters in Choghart iron mine using P-wave velocity

Nourani

Moghadder

Safari

2017

Journal of Rock Mechanics and Geotechnical Engineering

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Engineering rock mass classification, based on empirical relations between rock mass parameters and engineering applications, is commonly used in rock engineering and forms the basis for designing rock structures. The basic required data may be obtained from visual observation and laboratory or field tests. However, owing to the discontinuous and variable nature of rock masses, it is difficult for rock engineers to directly obtain the specific design parameters needed. As an alternative, the use of geophysical methods in geomechanics such as seismography may largely overcome this problem. In this study, 25 seismic profiles, with the total length of 543m have been scanned to determine the geomechanical properties of the rock mass in Blocks I, III and IV-2 of the Choghart Iron Mine. Moreover, rock joint measurements and sampling for the laboratory tests were conducted. The results show that the RMR and Q values have a close relation with P-wave velocity parameters, including P-wave velocity in field (VPF), P-wave velocity in the laboratory (VPL) and the ratio of VPF to VPL (K P ), which, respectively, are P-wave velocity in the field, P-wave velocity in the laboratory and the ratio of VPF to the VPL. However, Q value, totally, has more correlation coefficient and less error than the RMR. In addition, rock mass parameters including Rock Quality Designation (RQD), uniaxial compressive strength (UCS), joint roughness coefficient (JRC) and Schmidt number (RN) show close relationship with P-wave velocity. Thus, an equation based on these parameters was obtained based on these parameters in order to estimate the p-wave propagation velocity in the rock mass with a 91% correlation coefficient. The study of the velocity in two orthogonal directions and the results of the joint study show that the wave velocity anisotropy in rock mass may be used as an efficient tool to assess the strong and weak directions in rock mass. IntroductionRock mass classification is one of the most efficient tools in rock mechanics and is an essential element of feasibility studies prior to any excavation or disturbances made to rock. In most cases, a rock mass is so complex and heterogeneous that its qualifications are hard discerned by conventional tests. In these cases, geophysical methods such as seismography may be useful for estimating the properties of rock mass. Generally, the transmission velocity of the seismic waves in the rock mass depends on parameters such as density and rock strength, water condition, stress and number, orientation, spacing, separation, roughness, weathering and type of filler material for discontinuities. So, all of the parameters involved in a classification system such as Q and RMR affect the seismic wave velocity as well. Therefore, it is possible to obtain the variations of Q and RMR as a function of the seismic wave velocity parameters. Very useful studies have been conducted in this field. For example, Barton (1991) proposed a basic model for the study of the relationship between the P-wave velocity and the Q...

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“…These surveys would have used relatively low frequency geophones (8 -14 Hz) but, as an example of the versatility of this method, Rucker (2003) also used closely spaced high frequency 28-Hz geophones (mounted on large up-turned metal clips) inside a building to confirm poor ground compaction (in the top 3 m) beneath a solid floor. More recently it has been applied in an urban environment on the construction of a new railway for the KTX (Korea Train eXpress), where it was used to determine -3 -14/07/2011 the best tunnel route in tandem with a derived rock mass rating (Cha et al 2006). The method is attractive for investigating the near surface (< 100m) for several reasons: field data can be collected efficiently using existing standard seismograph and vertical P -wave geophones as used in refraction studies; it requires no triggered source of wave energy; it works best in a seismically noisy urban setting, where vehicular traffic and cultural noise in general, provide the necessary surface waves that this method analyses; it can model velocity reversals with depth, unlike seismic refraction, which is inherently 'blind' to them and only practicable in normally dispersive ground conditions, i.e.…”

Section: Introductionmentioning

confidence: 99%

Refraction microtremor (ReMi) to determine the shear-wave velocity structure of the near surface and its application to aid detection of a backfilled mineshaft

Raines

Gunn

Morgan

et al. 2011

QJEGH

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Passive refraction microtremor (ReMi) surveys utilise standard field seismic-refraction recording equipment and linear geophone arrays to record ambient background noise due to microtremors caused by natural and anthropogenic activities. The technique relies upon the detection of coherent phases of Rayleigh waves that have propagated along the axis of the geophone array, which is the same mode of propagation that causes ground roll on standard refraction surveys. Rayleigh wave propagation is confined within one wavelength of the surface, causing dispersion because waves with longer wavelengths (lower frequencies) are controlled by ground stiffness and density properties at greater depths. Field records that include coherent modes of dispersive Rayleigh wave propagation along the field array are processed using slowness (reciprocal of the phase velocity)-frequency transformations to extract the phase velocity-frequency dispersion curves. A series of dispersion curves are extracted by processing the field records of sub-groups including 6-8 geophones from which, 1D shear wave velocity-depth profiles are constructed and attributed to the centre of each array sub-group. In this survey, nine overlapping sub-groups of 8 geophones were selected along the whole field array of 24 geophones equi-spaced over 69 m. A 2D shear wave velocity section was created by infilling a grid between each of the velocity-depths profile using an anisotropic inverse distance weighting algorithm. Interpretation of the 2D section included the identification of: reworked ground comprising colliery spoil and clay to around 5 m below ground level associated with shear wave velocities from 100 -700 m/s; deeper strata within the host formation associated with higher velocities that increased in depth to above 1000 m/s below 10 m bgl; a backfilled mineshaft and a backfilled sandstone quarry at depths below 7 m associated with low velocity perturbations within the background host velocity structure. Key recommendations from this case study include the use of low-frequency geophones to increase the depth of investigation and recording of high frequencies at reduced geophone spacings to increase near surface resolution. Mike RainesShear wave velocity structure about a mineshaft

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Application of Linear-Array Microtremor Surveys for Rock Mass Classification in Urban Tunnel Design

Cited by 14 publications

References 1 publication

Geophysical investigation of landslides : a review

Geophysical investigation of landslides : a review

Classification and assessment of rock mass parameters in Choghart iron mine using P-wave velocity

Refraction microtremor (ReMi) to determine the shear-wave velocity structure of the near surface and its application to aid detection of a backfilled mineshaft

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