Correlation of N value with S-wave velocity and shear modulus

Imai, Toshiaki; Tonouchi, Keiji

doi:10.1201/9780203743959-11

Cited by 118 publications

(59 citation statements)

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“…4. It can be seen that the measured Vs of clays lies within the Vs predicted by Ohta and Goto [16], Imai & Tonouchi Imai [17], Jinan [20] for geological age Holocene (H) & geological deposition Alluvium (A), therefore, the average of these bounding correlations is applied to SPT to develop Vs profiles. For the gravelly soils, the measured data points lie within the Andrus [22], Yoshida, et al [21] and Ohta and Goto [16] correlations therefore, the average of these bounding correlations is applied to SPT to develop Vs profiles of gravelly soils.…”

Section: Fig 3 Distribution Of Borehole Depths Used In Current Studysupporting

confidence: 68%

“…However, numerous SPT-Vs correlations are available for the wide range of soils in literatures. Available correlations in literature were evaluated for clay [3,[15][16][17][18][19][20] and sandy gravel [16,21,22] soils by comparing with available measured Vs profiles. The selected correlations were applied to SPT-N data to develop Vs profiles.…”

Section: A Study Areamentioning

confidence: 99%

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GIS based Vs30, Vsz & Dbed rock Mapping for the Shallow Sites of Islamabad, Pakistan

Shahkar

Arshad

Sadiq

et al. 2021

Journal of Applied and Emerging Sciences

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The location of Pakistan is in a collision zone among the Eurasian and Indian plate boundaries. The geological framework of the Northwest Himalaya makes Northern Pakistan susceptible to frequent moderate to major earthquakes. The devastating earthquake of October 8, 2005 caused 87,000 deaths, 2.8 million displacements and financial loss of 200 Billion USD equivalent to 6% GDP of Pakistan. Islamabad is in seismically active region, the studies conducted for this region addresses the poor soil conditions, nonengineering construction practices and high level of seismic shaking. However, none of these studies provided readily available ground maps (top 30m time average shear wave velocity Vs30, average soil shear wave velocity Vsz & depth to bed rock Dbed rock) based on site specific geotechnical database. Vs30, Vsz & Dbed rock are important parameters for the evaluation of dynamic site characteristics of shallow bed rock sites. In Pakistan, Uniform Building Code (UBC-1997) is currently practiced, and the site classification are defined using site specific Vs30. In this study, geotechnical borehole database of 57 sites of Islamabad was collected to develop GIS based Vs30, Vsz & Dbed rock maps using Standard Penetration Test value (SPT-N). The borehole database includes, SPT-N, soil description and unit weight of soil for the Islamabad sites. In order to develop shear wave velocity (Vs) profiles, the available Vs-SPT empirical correlations were evaluated where both SPT-N & Vs measured data is available. The average of selected bounding correlations was applied to SPT-N database to develop representative Vs profiles. Using these Vs profiles, Vs30, Vsz & Dbed rock GIS based maps were developed by applying Kriging interpolation in open source QGIS software. The proposed GIS maps can be used in preliminary earthquake design for seismic resilient earthquake design in Islamabad, Pakistan.

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Section: Fig 3 Distribution Of Borehole Depths Used In Current Studysupporting

confidence: 68%

Section: A Study Areamentioning

confidence: 99%

GIS based Vs30, Vsz & Dbed rock Mapping for the Shallow Sites of Islamabad, Pakistan

Shahkar

Arshad

Sadiq

et al. 2021

Journal of Applied and Emerging Sciences

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“…When the direct measurement of the V S profile is not determined, the use of multiple indirect methods (i.e., penetration-based V S correlations) is recommended; these methods require selecting a V S30 design according to the seismic design codes in many countries [38]. The site-specific correlations between the V S and penetration tests, such as the cone penetration test, SPT, and Becker penetration test, have been obtained previously [39][40][41][42][43]. However, the correlations exhibit certain limitations: (1) low coefficient of determination values, (2) local uncertainty based on low quality data, and (3) disregard of the characteristic deformation behaviors of soils.…”

Section: Geotechnical Datasetsmentioning

confidence: 99%

Terrain Proxy-Based Site Classification for Seismic Zonation in North Korea within a Geospatial Data-Driven Workflow

et al. 2021

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Numerous seismic activities occur in North Korea. However, it is difficult to perform seismic hazard assessment and obtain zonal data in the Korean Peninsula, including North Korea, when applying parametric or nonparametric methods. Remote sensing can be implemented for soil characterization or spatial zonation studies on irregular, surficial, and subsurface systems of inaccessible areas. Herein, a data-driven workflow for extracting the principal features using a digital terrain model (DTM) is proposed. In addition, geospatial grid information containing terrain features and the average shear wave velocity in the top 30 m of the subsurface (VS30) are employed using geostatistical interpolation methods; machine learning (ML)-based regression models were optimized and VS30-based seismic zonation in the test areas in North Korea were forecasted. The interrelationships between VS30 and terrain proxy (elevation, slope, and landform class) in the training area in South Korea were verified to define the input layer in regression models. The landform class represents a new proxy of VS30 and was subgrouped according to the correlation with grid-based VS30. The geospatial grid information was generated via the optimum geostatistical interpolation method (i.e., sequential Gaussian simulation (SGS)). The best-fitting model among four ML methods was determined by evaluating cost function-based prediction performance, performing uncertainty analysis for the empirical correlations of VS30, and studying spatial correspondence with the borehole-based VS30 map. Subsequently, the best-fitting regression models were designed by training the geospatial grid in South Korea. Then, DTM and its terrain features were constructed along with VS30 maps for three major cities (Pyongyang, Kaesong, and Nampo) in North Korea. A similar distribution of the VS30 grid obtained using SGS was shown in the multilayer perceptron-based VS30 map.

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“…Various correlation equations between the shear wave velocity and N-value have been proposed (Japan Road Association, 2012). Imai and Tonouchi (1982) proposed the following equation.…”

Section: Surface Wave Prospectingmentioning

confidence: 99%

Ground Survey Based on the Distribution of Surface Wave Velocity and Electrical Resistibility

Kawai¹,

Hamada²,

Nakashima³

2020

GEOMATE

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Geophysical exploration, which can explore the distribution of material properties underground, has, for less than the last half a century, been applied for prospecting groundwater and bedrock. Though simulation techniques have improved with greater sophistication of the constitutive model for soil material, comprehension of current soil conditions is important for accurately predicting the behavior of earth structures. Therefore, the importance of geophysical exploration is growing. Soil parameters are indirectly identified from physical parameters, such as wave velocity, electric conductivity and so on. In geophysical exploration, calibrating physical parameters with necessary soil parameters is required for individual soil material and has thus prevented the application of geophysical exploration at the site level. In this study, surface wave and electric prospecting were conducted at a site first investigated circumstantially by borings and other soundings. Then, the applicability of surface wave and electric prospecting were validated through their comparison. Next, geophysical explorations were conducted on a large-size embankment. Consequently, the applicable scope of this type of exploration was demonstrated, proving its applicability for geotechnical engineering sites.

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Correlation of N value with S-wave velocity and shear modulus

Cited by 118 publications

References 0 publications

GIS based Vs30, Vsz & Dbed rock Mapping for the Shallow Sites of Islamabad, Pakistan

GIS based Vs30, Vsz & Dbed rock Mapping for the Shallow Sites of Islamabad, Pakistan

Terrain Proxy-Based Site Classification for Seismic Zonation in North Korea within a Geospatial Data-Driven Workflow

Ground Survey Based on the Distribution of Surface Wave Velocity and Electrical Resistibility

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