• Title/Summary/Keyword: Suspension PS logging test

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A Comparative Study on Borehole Seismic Test Methods for Site Classification

  • Jung, Jong-Suk;Sim, Youngjong;Park, Jong-Bae;Park, Yong-Boo
    • Land and Housing Review
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    • v.3 no.4
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    • pp.389-397
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    • 2012
  • In this study, crosshole seismic test, donwhole seismic test, SPT uphole test, and suspension PS logging (SPS logging) were conducted and the shear wave velocities of these tests were compared. The test demonstrated the following result: Downhole tests showed similar results compared to those of crosshole tests, which is known to be relatively accurate. SPS logging showed reliable results in the case of no casing, i.e. in the rock mass, while, in the case of soil ground, its values were lower or higher than those of other tests. SPT-uphole tests showed similar results in the soil ground and upper area of rock mass compared to other methods. However, reliable results could not be obtained from these tests because SPT sampler could not penetrate into the rock mass for the tests.

A Case Study on Geotechnical Properties and Weathering Degree of Weathered Granite Rock (화강 풍화암의 지반특성 및 풍화도 평가에 대한 사례 연구)

  • Lee, Seung-Hwan;Yoo, Byeong Soo;Chung, Choong-Ki
    • Journal of the Korean Geotechnical Society
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    • v.33 no.12
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    • pp.127-139
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    • 2017
  • Site investigation including boring and various in-situ borehole test (Pressuremeter test, Borehole shear test, Downhole test, Suspension PS logging, Density logging) and X-ray fluorescence analysis for rock core sample were performed to estimate geotechnical properties and weathering degree of weathered granite rock in Goyang. Deformation modulus, shear strength parameter and shear wave velocity estimated through in-situ borehole test had a tendency to increase with depth. And several chemical weathering indices evaluated by X-ray fluorescence analysis had a general tendency of reducing weathering degree in accordance with depth. Also, relationship between VR determined as a representative weathering index and the geotechnical properties was analyzed.

Field Application of New Seismic Site Characterization Using HWAW(Harmonic Wavelet Analysis of Wave) Method (HWAW(Harmonic Wavelet Analysis of Wave) 방법을 이용한 새로운 탄성파 지반조사기법의 현장 적용)

  • 박형춘;김동수;이병식
    • Journal of the Korean Geotechnical Society
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    • v.20 no.6
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    • pp.51-59
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    • 2004
  • The evaluation of shear modulus is very important in various fields of civil engineering. In this paper, the site characterization method using HWAW method is applied to determine shear wave velocity profile of two test sites in order to verify the field applicability of HWAW method. Shear wave velocity profiles by HWAW method are compared with shear wave velocity profiles by SASW test and PS-Suspension Logging test. Through field applications, it is shown that HWAW method can minimize the effect of noise and lateral non-homogeneity of the site and determine detailed local shear wave velocity profile of site.

Investigation of S-wave Velocity Based on SPS Field Tests (부유형 PS(SPS) 속도검층을 통한 전단파 특성 고찰)

  • Jeong, Nam-Hoon;Lee, Chong-Kyu
    • Journal of the Korean Geotechnical Society
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    • v.24 no.10
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    • pp.161-174
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    • 2008
  • To investigate the characteristics of the shear wave velocity of cohesive soils and residual soils in Korea, Standard Penetration Test (SPT), Suspension PS Logging tests (SPS) and other soil tests were performed to analyze the shear wave velocity at each layer For these purposes, 2 study sites are selected: one is cohesive soils and the other is residual soils. As a results, new empirical formulas are proposed from the relationship between strength of the ground (N value) and shear wave velocity from the test data at each layer. In the case of cohesive soils, the proposed relationships are nearly similar to empirical formulas, however, in the case of residual soils there was a little difference between the empirical formulas and measured velocities in this study. Case examples for shear wave velocites are presented with depth, N-values and compared with Ohta et al. (1978) empirical formula.

Industry-University-Research Collaborative Geoscientific Study in Pocheon area for Groundwater Survey, Part I: Borehole Technology (포천지역 지하수기초조사 산학연 공동탐사 사례연구(I): 공내탐사기술)

  • Yu, Young-Chul;Lee, Sang-Tae;You, Young-Jun;Hwang, Se-Ho;Sin, Je-Hyun
    • 한국지구물리탐사학회:학술대회논문집
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    • 2005.05a
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    • pp.117-122
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    • 2005
  • The purpose of this study is to analyze a correlation between lithology, rock physical property and fracture zone by multiple-logging method, which includes optic borehole image, suspension type PS, resistivity, SP, natural gamma, density, caliper logging located in Ogar test area, Changsu, Pocheon-gun, Gyunggi Province. The outstanding geophysical logging responses particularly shown from lithology pattern, fracture zone, dike zone. in result, the depth of fracture zone which enable groundwater flow estimated at $67{\sim}69m$.

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Comparison of Correlation Equations between N value and Shear Wave Velocity (N값과 전단파 속도의 상관식 비교)

  • Kong, Jin-Young;Chae, Hwi-Young;Chun, Byung-Sik
    • Proceedings of the Korean Geotechical Society Conference
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    • 2010.03a
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    • pp.656-665
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    • 2010
  • Shear modulus has been recognized as one of the important soil properties in dynamic analysis of ground and can be calculated from in situ measurement of shear wave velocity. Field seismic tests are the most accurate but expensive methods to investigate dynamic ground characteristics. Due to that reason, empirical equations for estimating the shear wave velocity are widely used rather than conducting in-situ tests. The most common equations are based on the N value obtained in conjuctions with a standard penetration test. In this paper, the field datas of standard penetration test and suspension PS logging measured in 126 sites of Korea were summarized and the correlation equations between N value and shear wave velocity are suggested.

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Geophysical Imaging of Alluvial Water Table and the underlying Layers of Weathered and Soft Rocks (충적층 지하수면 및 그 하부의 풍화암/연암의 경계면 파악을 위한 복합 지구물리탐사)

  • Ju, Hyeon-Tae;Lee, Chul-Hee;Kim, Ji-Soo
    • The Journal of Engineering Geology
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    • v.25 no.3
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    • pp.349-356
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    • 2015
  • Although geophysical methods are useful and generally provide valuable information about the subsurface, it is important to recognize their limitations. A common limitation is the lack of sufficient contrast in physical properties between different layers. Thus, multiple methods are commonly used to best constrain the physical properties of different layers and interpret each section individually. Ground penetrating radar (GPR) and shallow seismic reflection (SSR) methods, used for shallow and very shallow subsurface imaging, respond to dielectric and velocity contrasts between layers, respectively. In this study, we merged GPR and SSR data from a test site within the Cheongui granitic mass, where the water table is ~3 m deep all year. We interpreted the data in combination with field observations and existing data from drill cores and well logs. GPR and SSR reflections from the tops of the sand layer, water table, and weathered and soft rocks are successfully mapped in a single section, and they correlate well with electrical resistivity data and SPS (suspension PS) well-logging profiles. In addition, subsurface interfaces in the integrated section correlate well with S-wave velocity structures from multi-channel analysis shear wave (MASW) data, a method that was recently developed to enhance lateral resolution on the basis of CMP (common midpoint) cross-correlation (CMPCC) analysis.