• Journal of the Korean Geotechnical Society
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• v.33 no.4
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• pp.17-24
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• 2017

Shear wave velocity (or shear modulus) of rock filled zone of CFRD is very important factor in the evaluation of performance of CFRD under the load such as earthquake. A shear wave velocity profile can be determined by surface wave method but this profile has been uncertainty caused by spatial variation of material property in rock filled zone. This uncertainty in shear wave velocity profile could be evaluated by the reliability based analysis which uses a coefficient of variation of material property to consider uncertainty caused by spatial variation of material property. In this paper, the possible 600 shear wave velocity profiles in rock filled zone of CFRD were generated using the method based on harmonic wavelet transform and 8 shear wave velocity profiles by HWAW method in the field, and the coefficients of variation of shear wave velocity with depth were evaluated for the rock filled zone of CFRD in Korea.

• Journal of the Korean Geotechnical Society
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• v.31 no.9
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• pp.17-27
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• 2015

We perform a series of experimental tests to evaluate whether the shear strength of clean sands can be reliably predicted from shear wave velocity. Isotropic drained triaxial tests on clean sands reconstituted at different relative densities are performed to measure the shear strength and bender elements are used to measure the shear wave velocity. Laboratory tests reveal that a correlation between shear wave velocity, void ratio, and confining pressure can be made. The correlation can be used to determine the void ratio from measured shear wave velocity, from which the shear strength is predicted. We also show that a unique relationship exists between maximum shear modulus and effective axial stress at failure. The accuracy of the equation can be enhanced by including the normalized confining pressure in the equation. Comparisons between measured and predicted effective friction angle demonstrate that the proposed equation can accurately predict the internal friction angle of granular soils, accounting for the effect of the relative density, from shear wave velocity.

• 한국지구물리탐사학회:학술대회논문집
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• 2007.06a
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• pp.7-23
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• 2007

The shear wave velocity is directly related to the deformation characteristic of soils which is an engineering property represented by the shear modulus. This feature presents an opportunity of advantageous utilization of the shear wave velocity for deformation analysis in geotechnical engineering applications, since the deformation modulus is determined on strong theoretical basis, whereas penetration resistances such as N by SPT or qc by CPT rely on empirical relations. Furthermore, it is an engineering property that can be evaluated by performing the same basic measurement in the laboratory and field, and various problems in geotechnical engineering can be dealt with economically and reliably when the field and laboratory methods are combined effectively. In this article, assessment of nonlinear deformation characteristic of soils based on synergic use of the field and laboratory test results is described, and representative case histories of geotechnical applications of the shear wave velocity are illustrated.

• The Journal of Engineering Geology
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• v.22 no.3
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• pp.293-307
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• 2012

Shear wave velocity is commonly invoked in explaining geophysical phenomena and in solving geotechnical engineering problems. In particular, the importance of shear wave velocity in geotechnical earthquake engineering has been widely recognized for seismic design and seismic performance evaluation. In the present study, various insitu seismic tests were performed to evaluate geotechnical dynamic characteristics at 183 sites in Korea, and shear wave velocity profiles with depth were determined to be representative of the dynamic properties at the investigated sites. Subsurface soil and rock layers at the target sites were reclassified into five geotechnical layers: fill, alluvial soil, weathered soil, weathered rock, and bedrock, taking into account their general uses in geotechnical earthquake engineering practice. Average shear wave velocity profiles for the five geotechnical layers were obtained by synthesizing the shear wave velocity profiles from seismic tests in the field. Based on the profiles, a representative shear wave velocity value was determined for each layer, for use in engineering seismology and geotechnical earthquake engineering.

• Earthquakes and Structures
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• v.23 no.4
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• pp.353-361
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• 2022

The dynamic behavior of a single pile was investigated by using analytical and numerical studies. The focus of this study was to develop the dynamic p-y curve of a pile for pseudo-static analysis considering the shear wave velocity of the soil by using three-dimensional numerical analyses. Numerical analyses were conducted for a single pile in dry sand under changing conditions such as the shear wave velocity of the soil and the acceleration amplitudes. The proposed dynamic p-y curve is a shape of hyperbolic function that was developed to take into account the influence of the shear wave velocity of soil. The applicability of pseudo-static analysis using the proposed dynamic p-y curve shows good agreement with the general trends observed by dynamic analysis. Therefore, the proposed dynamic p-y curve represents practical improvements for the seismic design of piles.

• Journal of the Korean Geotechnical Society
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• v.36 no.4
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• pp.31-39
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• 2020

Shear wave velocity (or shear modulus) is very important in the evaluation of seismic performance of a fill dam under an earthquake. A shear wave velocity profile can be determined by surface wave method such as HWAW and SASW methods but this profile has uncertainty caused by spatial variation of material property in a fill dam. This uncertainty in shear wave velocity profile could be considered using a coefficient of variation of material property in the reliability based analysis. In this paper, the possible 600 shear wave velocity profiles in the core and rockfill zone of fill dam were generated by the random shear wave velocity profile generation method, proposed by Hwang and Park, based on the field shear wave velocity profiles determined by the HWAW and SASW methods. And, through the statistical analysis of generated shear wave velocity profiles in the fill dam, the coefficient of variation (COV) of shear wave velocity with depth were evaluated for the core and rock filled zone of fill dam in Korea.

• 한국지구물리탐사학회:학술대회논문집
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• 2007.06a
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• pp.75-79
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• 2007

To investigate the shear-wave velocity structures of the Korean peninsula, exploded seismic signals were recorded for 120 s along a 294-km WNW-ESE line and 150 s along a 335-km NNW-SSE line in 2002 and 2004, respectively. First arrival times of shear wave were inverted to derive the velocity tomograms. Initial shear-wave 1-D models were built using the initial P-wave velocity models used by Kim et al. and $V_p/V_s$ ratios of the IASP91 model. The raypaths indicate existence of mid-crust interfaces at the depth of 2-3 km and 16 km. The deepest significant interface corresponding to the Moho discontinuity varies in depth from 32 km to 36 km. The refraction velocity along the interface varies from 4.4 km/s to 4.6 km/s. The velocity tomograms also indicate existence of a low-velocity zone at the depth of 7.8 km under the Okchon fold belt.

• Journal of the Korean Geotechnical Society
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• v.31 no.11
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• pp.25-31
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• 2015

Elastic behavior of the railway roadbed which supports the repeating dynamic loads of the train is mainly affected by the shear modulus of the upper roadbed. Therefore, shear wave velocity estimation of the uniformly compacted roadbed can be used to estimate the elastic behavior of the railway roadbed. The objective of this study is to suggest the relationship between the dynamic cone penetration index (DCPI) and the shear wave velocity ($V_s$) of the upper roadbed in order to estimate the shear wave velocity by using the dynamic cone penetration test (DCPT). To ensure the reliability of the relationship, the dynamic cone penetration test and the measurement of the shear wave velocity are conducted on the constructed upper roadbed. As a method for measurement of the shear wave velocity, cross hole is used and then the dynamic cone penetration test is performed at a center point between the source and the receiver of the cross hole. As a result of the correlation of the dynamic cone penetration index and the shear wave velocity at the same depths, the shear wave velocity is estimated as a form of involution of the dynamic cone penetration index with a determinant coefficient above 0.8. The result of this study can be used to estimate both the shear wave velocity and the strength of the railway roadbed using the dynamic cone penetrometer.

• Journal of Korean Tunnelling and Underground Space Association
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• v.16 no.2
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• pp.225-236
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• 2014

Shear wave velocity was used to estimate the geotechnical characteristics (void ratio and shear strength) of ground near an underground rainfall storage facility. An oedometer cell was utilized to measure the shear wave velocity and the displacement of specimens. Shear strengths were obtained by direct shear tests. The relationships along the shear wave velocity, void ratio, and shear strength were verified and used to infer the shear strength profile with the depth. In addition, changes in shear strength due to the construction of the underground rainfall storage system were estimated using the suggested method. The results show that the in-situ shear strength deduced from the shear wave velocity-void ratio-shear strength relationship is in good agreement with that obtained from an in-situ investigation (SPT).

• Smart Structures and Systems
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• v.7 no.4
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• pp.275-287
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• 2011

The behaviors of saturated soils such as compressibility and permeability are distinguished by preconsolidation stress. Preconsolidation stress becomes an important design parameter in geotechnical structures. The goal of this study is to introduce a new method for the evaluation of preconsolidation stress based on the shear wave velocity at small strain, using Busan, Incheon, and Gwangyang clays in Korea. Standard consolidation tests are conducted by using an oedometer cell equipped with bender elements. The preconsolidation stresses estimated by shear wave velocity are compared with those evaluated by the Casagrande, constrained modulus, work, and logarithmic methods. The preconsolidation stresses estimated by the shear wave velocity produce very similar values to those evaluated by the Onitsuka method (one of the logarithmic methods), which yields an almost real preconsolidation stress. This study shows that the shear wave velocity method provides a reliable method for evaluating preconsolidation stress and can be used as a complementary method.