• Journal of the Korean GEO-environmental 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.

• 기술발표회
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• s.2006
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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.

• Proceedings of the Korean Geotechical Society Conference
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• 2000.03b
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• pp.599-606
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• 2000

본 연구는 피에조콘(Piezocone) 관입 시험에 의한 과잉간극수압의 소산(Dissipation)특성을 파악하기 위하여, 실측된 소산실험 결과치와 Gupta & Davidson에 의해 개발된 연속 공동확장이론(Successive Cavity Expansion Theory) 모델을 비교하였고, 그 경험적 이론의 적합성을 규명하였다. 연속 공동확장 이론이란, 콘 관입이 유발하는 관입 주변지반의 변환 메커니즘을 연속적인 공동확장의 전개과정로 파악할 때, 관입주변의 연속적 공동확장 영역에서 발생된 과잉간극수압들은 연속적으로 소산되어지고, 결국에는 관입멈춤직후 얻게 되는 소산시험의 결과도 이러한 과잉간극수압의 연속적 소산 메커니즘으로부터 그 영향을 받는다는 개념이다. 본 연구의 실험방법은 Piezocone 관입을 위한 연약모형지반 조성을 위하여 초대형 Slurry Consolidometer에 Slurry를 45일간 압밀시킨후 Calibration Chamber(Louisiana State University Calibration Chamber System)에 옮긴 후 2차 압밀시키는 Two-Stage Consolidation Method를 사용하였다. 또한 모형지반내에 8개의 Piezometers를 설치하여 Piezometers를 설치하여 Piezocone 관입시 유발되는 지반 내에서의 과잉간극수압의 변환을 측정하였다. 실험결과와 이론 예측치를 비교함으로써 연속 공동확장이론 모델은 u$_2$형식의 피에조콘 관입 소산시험 결과들과 잘 들어맞는 모습을 보여줬으나, 관입으로 인한 주변 지반의 과잉간극수압의 소산변화는 정성적으로만 모사 되는 모습을 보여줬다.

• Journal of the Korean Geotechnical Society
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• v.23 no.12
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• pp.53-60
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• 2007

A program for predicting rate of penetration of sheet pile using cone penetration test results was developed. Especially, energy consumption occurring from lateral vibration of sheet pile was estimated quantitatively in order to overcome overprediction of rate of penetration for shallow depths of pile installation. Penetration rates of pile calculated from developed program were compared with those of field test. Predicted rates of pile penetration for the depths to 12m were $47%{\sim}120%$ of the measured values. As pile penetration depth decreases, the difference between the predicted rate of penetration and the measured rate of penetration decreases.

• Proceedings of the Korean Geotechical Society Conference
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• 2000.03b
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• pp.559-566
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• 2000

본 연구에서는 비등방성 응력조건 하에서 콘 관입속도가 콘 관입시험 결과에 미치는 영향을 연구하기 위하여 유한요소해석 및 Calibration Chamber를 이용한 Miniature Piezocone의 관입시험이 수행되었으며 그 결과를 비교 분석하였다. 비등방성을 고려하기 위하여 Anisotropic Soil Model이 유한요소해석에 이용되었으며 LSU/CALCHAS(Louisiana State University Calibration Chamber System)가 Miniature Piezocone의 관입시험에 이용되었다. 콘 관입속도의 영향이외에도 OCR 및 필터위치의 영향을 고찰하였다.

• The Journal of Engineering Geology
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• v.31 no.4
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• pp.541-547
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• 2021

To assess the stability of a slope and the likelihood of its loss or collapse requires information about the ground, such as the composition of the stratum and its mechanical characteristics. This information is generally gathered through standard penetration testing (SPT) and cone penetration testing. SPT is not widely used due to problems with accessing slopes, most of which are steep and without ramps. A drop cone penetrometer, a portable device that can make up for these shortcomings, can be used in a limited way in some circumstances. Therefore, we developed a portable drilling machine and a small dynamic cone penetration test module that can easily access a slope site and perform SPT. The correlation of the developed system's results with those from SPT was analyzed. Analysis of the correlation between the energy shear rate passing to the load during the different test types established that the energy shear rate is reflected in the test result. The correlation between corrected dynamic cone penetration testing and corrected SPT was N_d' = 3.13 N'.

• Journal of the Korean Geotechnical Society
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• v.23 no.3
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• pp.133-140
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• 2007

DCM (Deep Cement Mixing Method) has been applied to build structures such as self-supported earth retaining walls. DCM columns should be penetrability into the stiff layer to assure the self-supporting ability. On the penetration increase of blade attached to the DCM mixing tools, a spiral mixing blade has been revised. Penetration characteristics of spiral blades in the stiff soil layer were evaluated through Gimhae and Incheon areas. The spiral mixing blades could penetrate into the stiff soil layers which have the N-value of greater than 30 although the penetration rate is somewhat slow. Penetration characteristics and economical efficiency should be discussed to determine the critical depth of the spiral mixing blade because the penetration efficiency can decrease in the stiff layer in this paper.

• 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.

• 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.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.38 no.3
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• pp.429-438
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• 2018

Cone and T-bar penetrometers have been frequently used to estimate the undrained shear strength of clay. For small-size model tests, miniature penetrometers should be used but their correlation factors have not been well published. In this study, a testing setup was developed to derive empirical factors of the miniature cone and T-bar penetrometers. A 350mm-diameter chamber and kaolin clay were utilized to prepare soil specimens consolidated under four different pre-consolidation pressures controlling undrained shear strength. Two miniature cones with two diameters of 10-mm and 16-mm and a T-bar penetrometer with 10-mm diameter were used to investigate boundary effect, penetration rate effect, and diameter and shape effect. Unconsolidated-undrained triaxial tests were carried out with samples taken from the specimens to measure undrained shear strength. Finally, empirical factors for the penetrometers were constructed to correlate tip resistance to undrained shear strength.