• Title, Summary, Keyword: 표준관입시험

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Hammer Energy Level of SPT in Korea (표준관입시험의 해머에너지 수준)

  • 이호준;박용원
    • Geotechnical Engineering
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    • v.12 no.5
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    • pp.117-126
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    • 1996
  • In spite of many advantages such as the simplicity in test procedure, Standard Penetration Test(SPT) results contain some errors caused by the variability of test equipment, instruments and test procedures. Especially, it is inevitable that the measured SPT hammer energy is different from the theoretical value because of energy loss. In this paper, the hammer energy level is measured during the performance of the field SPT in Korea by using a ultra-sonic system and PC.program. As the results of this study, the average hammer energy ratio of the R-P hammer and the Trip hammer is calculated at 64.2%, and at 75.0% respectively. The average energy ratio of the SPT for the R-P hammer is calculated at 46% and at 54% for the Trip hammer, by applying the rod energy ratio 0.72.

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Deduction of Correlations between Shear Wave Velocity and Geotechnical In-situ Penetration Test Data (전단파속도와 지반공학적 현장 관입시험 자료의 상관관계 도출)

  • Sun, Chang-Guk;Kim, Hong-Jong;Chung, Choong-Ki
    • Journal of the Earthquake Engineering Society of Korea
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    • v.12 no.4
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    • pp.1-10
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    • 2008
  • Shear wave velocity($V_S$), which can be obtained using various seismic tests, has been emphasized as representative geotechnical dynamic characteristic mainly for seismic design and seismic performance evaluation in the engineering field. For the application of conventional geotechnical site investigation techniques to geotechnical earthquake engineering, standard penetration tests(SPT) and piezocone penetration tests(CPTu) together with a variety of borehole seismic tests were performed at many sites in Korea. Through statistical modeling of the in-situ testing data, in this study, the correlations between $V_S$ and geotechnical in-situ penetrating data such as blow counts(N value) from SPT and piezocone penetrating data such as tip resistance ($q_t$), sleevefriction($f_s$), and pore pressure ratio($B_q$) were deduced and were suggested as an empirical method to determine $V_S$. Despite the incompatible strain levels of the conventional geotechnical penetration tests and the borehole seismic tests, it is shown that the suggested correlations in this study are applicable to the preliminary estimation of $V_S$ for Korean soil layers.

Shear Strength and Compressibility of Oyster Shell-Sand Mixtures for Sand Compaction Pile (SCP공법 적용을 위한 굴패각-모래 혼합토의 전단과 압축특성)

  • Yoon Gil-Lim;Yoon Yeo-Won;Chae Kwang-Seok;Kim Jae-Kwon
    • Journal of the Korean Geotechnical Society
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    • v.20 no.9
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    • pp.17-23
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    • 2004
  • Strength and deformation characteristics of oyster shell-sand mixtures were investigated to utilize waste oyster shell being treated as a waste material. Standard penetration test (SPT) is a common method to obtain in-situ strength in sand. However, in case of oyster shell-sand mixtures, there was no information between SPT N-value and internal friction angle of mixture soils. In this paper SPT experiments from several large scaled model chamber tests and large scaled direct shear tests were carried out with varying unit weight of oyster shell-sand mixtures. Appropriate correlations were in tile study observed among N-value, unit weight and internal friction angle, which make it possible to estimate in-situ strength from SPT and the coefficient of volume compressibility from the confined compression tests to compute the settlement of oyster shell-sand mixtures.

Standard Penetration Test Performance in Sandy Deposits (모래지반에서 표준관입시험에 따른 관입거동)

  • Dung, N.T.;Chung, Sung-Gyo
    • Journal of the Korean Geotechnical Society
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    • v.29 no.10
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    • pp.39-48
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    • 2013
  • This paper presents an equation to depict the penetration behavior during the standard penetration test (SPT) in sandy deposits. An energy balance approach is considered and the driving mechanism of the SPT sampler is conceptually modeled as that of a miniature open-ended steel pipe pile into sands. The equation consists of three sets of input parameters including hyperbolic parameters (m and ${\lambda}$) which are difficult to determine. An iterative technique is thus applied to determine the optimized values of m and ${\lambda}$ using three measured values from a routine SPT data. It is verified from a well-documented record that the simulated penetration curves are in good agreement with the measured ones. At a given depth, the increase in m results in the decrease in ${\lambda}$ and the increase in the curvature of the penetration curve as well as the simulated N-value. Generally, the predicted penetration curve becomes nearly straight for the portion of exceeding the seating drive zone, which is more pronounced as soil density increases. Thus, the simulation method can be applied to extrapolating a prematurely completed test data, i.e., to determining the N value equivalent to a 30 cm penetration. A simple linear equation is considered for obtaining similar results.

Scale Effects and Field Applications for Continuous Intrusion Miniature Cone Penetrometer (연속관입형 소형콘관입시험기에 대한 크기효과 및 현장적용)

  • Yoon, Sungsoo;Kim, Kyu-Sun;Lee, Jin Hyung;Shin, Dong-Hyun
    • Journal of The Korean Society of Civil Engineers
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    • v.33 no.6
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    • pp.2359-2368
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    • 2013
  • Cone penetration tests (CPTs) have been increasingly used for site characterizations. However, the site investigations using CPTs are often limited due to soil conditions depending on the cone size and capacity of the CPT system. The small sectional area of a miniature cone improves the applicability of the CPT system due to the increased capacity of the CPT system. A continuous intrusion system using a coiled rod allows fast and cost effective site investigation. In this study, the performance of the continuous intrusion miniature cone penetration test (CIMCPT) system has been evaluated by comparison tests with the standard CPT system at several construction sites in Korea. The results show that the CIMCPT system has a same performance with the CPT system and has advantages on the mobility and applicability. According to field verification tests for scale effect evaluation, the cone tip resistance evaluated by CIMCPT overestimates by 10% comparing to standard CPTs. A crawler mounted with the CIMCPT system has been implemented to improve accessibility to soft ground, and has shown improvement over the truck type CIMCPT system. Therefore, the improved CIMCPT system can be utilized as a cost effective and highly reliable soil investigation methodology to detect the depth of soft ground and to evaluate soil classification.

Empirical Estimations of Soil Constants Using Standard Penetration Test N Value (표준관입시험 N값을 활용한 지반정수의 경험적 산정)

  • Gang, ByeungJu;Hwang, Bumsik;Cho, Wanjei
    • Journal of the Korean Geoenvironmental Society
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    • v.19 no.6
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    • pp.5-12
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    • 2018
  • Domestic design manuals provide various empirical relationships of design parameters of soils with N values from the Standard Penetration Test (SPT), which can be widely used in the basic design process as well as during the construction process. However, the currently used empirical relationships are based on the data from foreign countries and are rarely evaluated with domestic data with currently used site investigation techniques. Therefore, in this study, those empirical relationships and conversion tables are evaluated with the geotechnical information in the Integrated DB Center of National Geotechnical Information and new empirical relationships are newly proposed with the consideration of domestic geotechnical conditions.

Determination of the Overconsolidation Ratio using the Piezocone Penetration Test (피에조콘 관입시험에 의한 과압밀비 산정에 관한 연구)

  • Lee, Ki-Se;Shin, Won-Tae;Goo, Nam-Shil;Kim, Hak-Joon
    • The Journal of Engineering Geology
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    • v.17 no.3
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    • pp.351-358
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    • 2007
  • Using the results of the Piezocone Penetration Test(PCPT) which were executed at the Yangsan-Mulgum site, the applicability of the interpretation methods far estimating the OCR(Overconsolidation Ratio) of soft clay was evaluated. At the same time, the results from the laboratory tests using the total of 172 undisturbed soft clay samples taken from the 44 bore holes of the Yangsan-Mulgum site were used to compare the OCR values obtained from the consolidation test with those from the PCPT. The relationship between the predicted overconsolidation ratio($OCR_p$) using the PCPT and the measured overconsolidation ratio($OCR_c$) from the laboratory consolidation tests are investigated and presented in this study. The $OCR_p$ by using the Powell et al.'s method for non-fissured clay from the results of the PCPT shows the best relationship with the $OCR_c$ obtained from the laboratory consolidation test.

Prediction of Shear Wave Velocity on Sand Using Standard Penetration Test Results : Application of Artificial Neural Network Model (표준관입시험결과를 이용한 사질토 지반의 전단파속도 예측 : 인공신경망 모델의 적용)

  • Kim, Bum-Joo;Ho, Joon-Ki;Hwang, Young-Cheol
    • Journal of the Korean Geotechnical Society
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    • v.30 no.5
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    • pp.47-54
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    • 2014
  • Although shear wave velocity ($V_s$) is an important design factor in seismic design, the measurement is not usually made in typical field investigation due to time and economic limitations. In the present study, an investigation was made to predict sand $V_s$ based on the standard penetration test (SPT) results by using artificial neural network (ANN) model. A total of 650 dataset composed of SPT-N value ($N_{60}$), water content, fine content, specific gravity for input data and $V_s$ for output data was used to build and train the ANN model. The sensitivity analysis was then performed for the trained ANN to examine the effect of the input variables on the $V_s$. Also, the ANN model was compared with seven existing empirical models on the performance. The sensitivity analysis results revealed that the effect of the SPT-N value on $V_s$ is significantly greater compared to other input variables. Also, when compared with the empirical models using Nash-Sutcliffe Model Efficiency Coefficient (NSE) and Root Mean Square Error (RMSE), the ANN model was found to exhibit the highest prediction capability.

Evaluation of Shear Wave Velocity Profiles by Performing Uphole Test Using SPT (표준관입시험을 이용한 업홀시험에서 전단파 속도 주상도의 도출)

  • 김동수;방은석;서원석
    • Journal of the Korean Geotechnical Society
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    • v.19 no.2
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    • pp.135-146
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    • 2003
  • Uphole test is a seismic field test using receivers on ground surface and a source in depth. In this paper, the uphole test using SPT(standard penetration test) which is economical and reliable for obtaining shear wave velocity profile was introduced. In the proposed uphole test, SPT sampler which is common in site investigation, was used as a source and several 1Hz geophones in line were used as receivers. Test procedures in field and interpretation methods for obtaining interval times and for determining shear wave velocity profile considering refracted ray path were introduced. Finally, uphole test was performed at three sites, and the applicability of the proposed uphole test was verified by comparing wave velocity profiles determined by the uphole test with the profiles determined by downhole test, SASW test and SPT-N values.