• Title, Summary, Keyword: 표준관입시험

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Correlation Analysis between DCPT Value and SPT Value (동적콘관입시험값과 표준관입시험값의 상관성 분석)

  • Lee, Bongjik;Lee, Jongkyu
    • Journal of the Korean Geoenvironmental Society
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    • v.15 no.8
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    • pp.23-30
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    • 2014
  • In-situ penetration tests have been widely used in geotechnical engineering for site investigation in support of analysis and design. Standard Penetration Test (SPT) and Dynamic Cone Penetration Test (DCPT) are typical dynamic sounding. DCPT was originally developed as an alternative for evaluating the properties of subgrade soils. The main advantages of DCPT are that it is fast, inexpensive, and it is particularly useful in delineating areas of weak soils overlying stronger strata and in quickly assessing the variability of the soil conditions. But lack of standardization is main reason that this test method has not been advanced more in recent years. In this study, it is clarified the correlation with the SPT blow count, N from DCPT data using big DCP eqipment. Regression analysis and correlationship analysis were conducted with the data from relationship between SPT and DCPT. The analysis results showed that the convert fact are in the range of 1.12~1.31 with variation with soil property.

The Ground Investigation Technique of Railway Using Pagani Cone Test (Pagani Cone Test를 이용한 철도노반 조사 기법 연구)

  • Cho, Eun-Kyung;Cho, Kook-Hwan
    • Journal of the Korean Society for Railway
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    • v.19 no.6
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    • pp.792-801
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    • 2016
  • Standard Penetration Test (SPT) and Cone Penetration Test (CPT) are widely used in geotechnical investigation methods for railway roadbed. However, SPT can not be used on the Railway track, since the equipment may contact to the electric lines. However, a portable equipment can be used for geotechnical investigation without electrical hazard. Dynamic Cone Penetrometer (DCP) is one of representative portable equipments. A normal portable DCP has usually not enough driving energy and the rigidity of cone-rod, so it is impossible to investigate the required investigate penetration depth. In this study, The adaptability of Pagani cone test which is one of portable dynamic cone penetrometer is studied and compared with SPT-N data. As a result of this study, the proposed correlation factors between Pagani cone test and SPT-N values after corrections is 1.48 for sandy soil and 1.33 for clayey soil.

A Study of Correlation between SPT N-value and Exerted Electrical Energy Required for Ground Drilling II : Application Study (Field Pilot Test) (지반굴착에 소요되는 전기에너지와 표준관입시험 N값과의 상관관계 연구 II : 적용성 평가(현장시험시공))

  • Choi, Changho
    • Journal of the Korean Geosynthetics Society
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    • v.11 no.4
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    • pp.55-62
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    • 2012
  • In this application study, field pilot tests were performed to evaluate the validity of a proposed formula between the exerted electrical energy and SPT N-value based on the result of the basic study. Measurement sensors and recording system were developed to obtain exerted motor current and drilling depth in a field. By using the correlation formula proposed in the basic study, the measured motor current and boring speed were applied to predict SPT N-value and the predicted N-values were compared to SPT N-value of site exploration. From the comparisons it is verified that the exerted electrical energy to bore ground might be used to predict SPT N-value and pile tip location.

Soil Investigation by Helical Probe Test (나선심사시험에 의한 지반조사기법)

  • ;Yokel, Felix Y.
    • Geotechnical Engineering
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    • v.3 no.4
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    • pp.31-40
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    • 1987
  • A helical probe test (HPT) suitable for in.situ soil exploration to a shallow depth and compaction control were developed and tested in different soils alongside traditional in-situ tests, including Standard Penetration Test (SPT), Cone Penetration Test (CPT) and in-situ density test. The helical probe test is economical and can be performed by a single person. The torque necessary to insert the probe Is used as a measure of soil characteristics. It was found that: the HPT test correlates well with the SPT test and the correlation is not sensitive to the soil type; the HPT test correlates well with the CPT test, but the correlation is sensitive to the soil type; the HPT torque provides a sensitive measure of relative compaction rind in-situ dry density of compacted soils; the reverse torque ratio decreases with increasing average grain sloe.

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Characteristics of Undrained Shear Strength and Development of Modified SPT on Very Soft Ground in Korea (국내 초연약지반의 비배수전단강도 특성 및 개량표준관입시험기 개발)

  • Jung, Hyuksang;Cho, Changkoo;Chun, Byungsik
    • Journal of the Korean Geoenvironmental Society
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    • v.10 no.6
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    • pp.105-115
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    • 2009
  • In this study, SPT, FV, and CPT tests were performed at five very soft grounds in southern coast of Korea to characterize the $S_u$ of very soft ground. In addition, a new modified SPT that is applicable to very soft ground was developed. Tests results showed that in very soft ground (N<2), the $S_u$ was lower than 12.5 kPa using the empirical N-Su correlation, and lower than 50 kPa and 65 kPa using vane shear test and CPT, respectively. It was shown that the results of in-situ tests were higher than those estimated from the N-Su correlation, and it was also demonstrated that the range of estimated $S_u$ was quite wide. New correlations that relate the modified SPT $N_m$ with Su from FV and CPT were developed, which are $S_u=1.76N_m-10.47$ and $S_u=1.82N_m-9.71$, respectively.

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A Study on the Determination of Construction Depth of Vertical Drain by Cone Resistance (콘 관입저항치를 이용한 수직배수재 타설심도 결정에 관한 연구)

  • Kim, Yeon-Jung;Kim, Nam-Ho;Shin Yun-Sup
    • 기술발표회
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    • pp.261-269
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    • 2006
  • Recently, piezocone penetration test is frequently used in order to estimate the characteristics of soft ground with standard penetration test; generally used in the past In this study, standard penetration test, piezocone penetration test, driving resistance of vertical drain were used in order to increase the confidence for determination of soft ground depth. And the compressible layer was determined by the comparison between the preconsolidation pressure and the designed increase pressure. As the results, the relation between standard penetration test and piezocone penetration test shows $q_c$=(1.09~1.63)N at the soft ground, determined by 5/30 N value. And $q_c$(1.21~1.98)N was shown at the point of compressible layer, evaluated by the preconsolidation pressure. And driving resistance of vertical drain is 70 f/$cm^2$ which is equal to 10kgf/$cm^2$ cone penetration resistance.

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A Study on the Determination of Construction Depth of Vertical Drain by Cone Resistance (콘 관입저항치를 이용한 수직배수재 타설심도 결정에 관한 연구)

  • Jang, Seo-Yong;Kim, Jong-Ryeol;Shin, Yun-Sup;Ma, Bong-Duk
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.10 no.5
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    • pp.163-170
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    • 2006
  • Recently, piezocone penetration test is frequently used in order to estimate the characteristics of soft ground with standard penetration test, generally used in the past. In this study, the correlation of standard penetration test, piezocone penetration test and driving resistance of vertical drain is analyzed in order to increase the confidence for determination of soft ground depth. As the results of each zone, the relation between standard penetration test and piezocone penetration test shows qc=(1.09~1.63)N at the soft ground, determined by 5/30 N value which is decided for soft ground criteria. And qc=(1.21~1.98)N was shown at the point of compressible layer, evaluated by the preconsolidation pressure. And driving resistance of vertical drain is $65{\sim}70kgf/cm^2$ which is equal to $10kgf/cm^2$ of cone penetration resistance.

A Study on the Correlation between Standard Penetration Resistance Value and Static Cone Penetration Resistance Value of the Soft Ground Subsurface of Yongdong Area (표준관입저항치와 정적콘관입저항치의 상관성에 관한 연구 - 영동지역의 연약지반을 중심으로 -)

  • Kim, Jinam;Park, Heunggyu
    • Journal of the Korean Geoenvironmental Society
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    • v.7 no.5
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    • pp.13-20
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    • 2006
  • We have conducted standard penetration tests and static cone penetration tests that are widely used the land base examination on the soft ground subsurface of Yongdong area, and examined the correlation between them. We have also made a comparative analysis of the correlation between the indoor tests on the materials collected on the site and on-the-spot penetration tests. The results are as follows : The relationship between Standard Penetration Test N-value and Dutch Cone Tset show $Q_c=1.93N+0.29$ for organic soil, $Q_c=2.19N+0.20$ for clay, $Q_c=2.34N+1.06$ for silt, $Q_c=3.02N+0.54$ for silty sand, and $Q_c=3.47N+0.46$ for sand. In this case of sand $Q_c/N$ increases when the soil particles are larger. The relationship between standard penetration test N-value and Unconfined Compression Strength $q_u$ show $q_u=0.11N+0.03$ for organic soil, $q_u=0.11N+0.25$ for clay, and $q_u=0.18N-0.03$ for silt.

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A Study of Correlation between SPT N-value and Exerted Electrical Energy Required for Ground Drilling I : Basic Study (Laboratory Soil Box Test) (지반굴착에 소요되는 전기에너지와 표준관입시험 N값과의 상관관계 연구 I : 기초연구(실내토조실험))

  • Choi, Changho
    • Journal of the Korean Geosynthetics Society
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    • v.11 no.4
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    • pp.45-53
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    • 2012
  • Ground drilling is a common method to conduct site investigation, soil improvement, and pile installation. In the point of construction ground drilling requires electrical energy to drill a hole in ground in which the energy exerts into the motor located on the head of auger and generates rotational power. In this paper it is verified that the exerted electrical energy is closely related to the strength characteristics of ground. Measurement sensors, recording system, and drilling system were developed to obtain exerted motor current and drilling depth and laboratory soil box tests were carried out. The measured motor current and boring depth were applied to predict SPT N-value and the prediction results were compared to SPT N-value of laboratory tests. The test results show that the exerted electrical energy to bore ground be a good index to estimate SPT N-value.

The Correlation Analysis between Dynamic Cone Penetration Test and Plate Loading Test Results for Evaluation of Dam Conditions (제체 상태 평가를 위한 동적 콘 관입시험과 평판재하시험 결과의 상관관계 분석)

  • Jung, Young-Hoon;Kim, Seongmin;Lim, Jeong-yeul
    • Journal of the Korean Geoenvironmental Society
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    • v.19 no.4
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    • pp.33-38
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    • 2018
  • The internal erosion due to poor compaction of the material was the main cause of collapse of the embankment in Korea. The assessment of the compaction state of the dam body was a very important check in the safety diagnosis of the embankment. In this study, the correlation between dynamic cone penetration test and plate loading test which is the most typical compaction evaluation technique was analyzed to verify the applicability of the dynamic cone penetration test in evaluating the compaction state of the dam body. The standard penetration tests were carried out six times to define soil properties and depth of the test site. The spatial distributions were obtained by the Kriging method after 15 times of plate loading tests and 47 times of dynamic cone penetration tests. The Pearson correlation coefficient between the spatial distribution of the plate loading test and the dynamic cone penetration test spatial distribution at the constant penetration depth was calculated. The load distribution in the plate loading test and the blow counts at penetration depths of 5 cm, 10 cm and 15 cm in the dynamic cone penetration test showed a weak positive correlation.