• 한국지구물리탐사학회:학술대회논문집
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• 2005.09a
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• pp.3-9
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• 2005

In order to obtain more reliable data for the information on the ground, a new site Investigation method is proposed, in which seismic waves (S-waves) generated by the Swedish Ram Sounding Test (SRS) are used. It is indicated that the energy transferred from the hammer to the rod in SRS's is much more stable, compared to SPT's. A series of SRS with measurements of seismic waves at the ground surface were carried out to clarify the characteristics of seismic wave propagation in the ground. As the results of comparison between seismic S-wave amplitudes and $N_d$ (blow count for 20 cm penetration in SRS), it was found that amplitudes of S-waves generated by SRS correlate well with $N_d$. The amplitude of the S-wave is thought to be more adequate parameter for the soil strength and rigidity than $N_d$.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.03a
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• pp.1083-1086
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• 2008

In this study, Estimate solutions of ultimate lateral resistances for lateral loaded piles are proposed using cone penetration values, $q_c$ values, as CPT results. Cone penetration values, $q_c$ values measured on clean sand layers, are represented by factors for relative densities, axial stresses, and lateral stresses which are important on analysis of sandy soil layers. Also, these factors are same factors to consider existed estimations of ultimate lateral capacity. In this study, estimation of ultimate lateral capacity for lateral loaded piles using CPT results is proposed, and this estimation is verified by adequate analysis for effective reliability.

• Geotechnical Engineering
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• v.6 no.3
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• pp.31-40
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• 1990

The soil deformation due to a pile penetration in sandy soils has been analysed in model pile penetration tests. To simulate the actual ground conditions, especially the in-situ stress levee the tests were performed in a calibration chamber where both the vertical and the horizontal stresses could be applied separately. The deformation was monitored via 5 earth pressure cells. The results, were compared with the theortical values based on the theory of cavity expansion.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.1C
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• pp.19-27
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• 2011

This paper evaluates the applicability of wave-based nondestructive methodologies and a penetration test for compaction quality measurements during road construction. To evaluate the physical and mechanical properties of compacted subgrade soil layers, soil stiffness gauge (SSG), time domain reflectometry (TDR), and miniature electro-mechanical systems (MEMS) accelerometers were used to nondestructively evaluate the soil response during and after compaction and dynamic cone penetrometer (DCP) profiles were used to evaluate the soil shear strength after compaction was completed. At the field site, two types of soils were compacted with four different compaction equipments and energies. Field testing results indicate that soil parameters evaluated by different testing methods, which are SSG, TDR, MEMS accelerometer, and DCP, are highly correlated. In addition, it is shown that the physical and mechanical tests deployed in this study can be used as alternative methods to the conventional compaction quality evaluation methods when assessing the overall quality and the engineering response of compacted lifts.

• Journal of the Korean Recycled Construction Resources Institute
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• v.8 no.4
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• pp.450-457
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• 2020

In this study, engineering characteristics such as flowability, segregation and compressive strength by age to derive fast hardening material mixing proportion using excavated soil. And based on optimal mixing proportion, field simulation experiment conducted in laboratory to examine the effectiveness of the method such as kelly ball drop test and soil penetration test for reviewing the following process. As as a result of evaluation, in case of kelly ball drop test and soil penetration test were securing the following process initiation time 3 hours after place CLSM. As results of these assessments, kelly ball drop test and soil penetration test were applicable for revewing following process in construction field besides unconfined compressive strength method.

• Proceedings of the Korean Geotechical Society Conference
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• 2003.03a
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• pp.701-708
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• 2003

Recently, piezocone penetration test is frequently conformed in order to estimate the characteristics of soft ground with standard penetration test, generally used in the past. The soil characteristics, such as cone penetration resistance, friction resistence and excessive pore water pressure, can be evaluated continuously through the piezocone penetration test. In Incheon International Airport 2nd phase site preparation, standard penetration test and piezocone penetration test 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~l.63)N at the soft ground, determined by 5/30 N value. And q$_{c}$=(1.21~l.98)N was shown at the point of compressible layer, evaluated by the preconsolidation pressure. These results were applied to determination for the depth of soft ground and to design the improvement for the soft clay.lay.

• Journal of Ocean Engineering and Technology
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• v.34 no.3
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• pp.202-207
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• 2020

A track-type underwater construction robot (URI-R) was developed by the Korea Institute of Ocean Science & Technology. Because URI-R uses tracks to move on the seabed, insufficient ground strength may hinder its movement. For smooth operation of URI-R on the seabed, it is important to determine the geotechnical properties of the seabed. To determine these properties, standard penetration test (SPT), cone penetration test (CPT), and sampling are used on land. However, these tests cannot be applied on the seabed due to a high cost owing to the vessel, crane, sampler, and analysis time. To overcome these problems, a free fall cone penetration tester (FFCPT) is being developed. The FFCPT is a device that acquires the geotechnical properties during impact/penetration/finish phases by free fall in water. Depth information is crucial during soil data acquisition. As the FFCPT cannot measure the penetration depth directly, it is estimated indirectly using acceleration. The estimated penetration depth was verified by results of real tests conducted on land.

• Geomechanics and Engineering
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• v.28 no.6
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• pp.625-636
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• 2022

The standard penetration test (SPT) obtaining the N value of the number of blows has been widely used in various subsurface conditions, including in weathered soil and rock on fresh bedrock, in geotechnical studies pertaining to the design of foundations and earth structures. This study examined the applicability of SPTs terminated conventionally after 50 blows for a penetration of less than 30 cm, particularly in weathered strata, at four sites in Korea. The N values obtained during practical SPTs are typically extrapolated linearly at 30 cm penetration, despite the possibility of a nonlinear relationship between blow counts and penetration. Such nonlinearity in weathered strata has been verified by performing special SPTs ensuring 30 cm penetration. To quantify the nonlinearity in dense strata, we conducted statistical regression analyses comparing the differences (DN) between the N values measured by the special SPTs and those extrapolated using the practical approach with the differences (DP) between the 30 cm penetration and the penetration during 50 blows. Bi-linear relationship models between DN and DP were subsequently proposed for determining the N values at 30 cm penetration in weathered strata. The N values reflecting nonlinearity could be determined from the linearly extrapolated N values by adding a modeled DN value.

• Journal of Biosystems Engineering
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• v.12 no.3
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• pp.1-6
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• 1987

The objective of this study is to develop a soil hardness tester which can estimate tillage resistance with tae travelling cone-penetrometer. For the study, a series of tests was performed using the cone penetrating in the horizontal direction. Based on the tests above, soil hardness was represented by travelling cone-index vs depth of cone penetration, travelling speed and moisture contents of the soil Resistance characteristics obtained from the experiments were compared with those by a vertical cone-penetrometer and the Yamanaka's soil hardness tester. Following conclusions were made from the study. 1. 8 to 9 peaks per one meter were detected in the resistance curve of cone penetration regardless of the travelling speed of cone-penetrometer when it penetrated the soil in the horizontal direction. This phenomenon seemed to be a similar one noticed in shearing pitch of plowing. 2. Cone index increased as travelling speed increased from 0.08m/sec to 0.5m/sec. 3. Linear relationship was found between the cone indices measured by the travelling coe-penetrometer and Yamanaka's hardness tester. 4. Increasing rate of the cone indices measured by vertical cone-penetrometer decreased as the depth of soil increased while the cone indices by the travelling cone-pentrometer increased linearly.

• Journal of the Korea Institute of Building Construction
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• v.7 no.1 s.23
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• pp.79-84
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• 2007

Selection of proper root barrier as destination part of greening is very important in Root penetration resistance plan. To select proper root barrier, it need to understand composition of greening part, size, kind of plant, connection with waterproofing layer. In this point of view, we have establish greening on the roof or concrete structure, not been understand the structural mechanism. It means that we misunderstood about purpose of greening and using it. So, chosen materials and construction method was not proper for greening, it caused water leakage and decrease performance of concrete structure. Therefore, we would suggest 5 items of test methods considering environmental condition for green roof. Watertightness by water of greening part, root penetration resistance test by root penetration, bacteria resistance by must or bacteria in soil, chemical resistance by rain and chemical agent of fertilizer, and load resistance by soil depth, size of plant. These suggested test methods could be referred as guideline to test in green roof system because of not exist any performance appraisal guideline or standard. Consequently, it should be analysis as technical and institutional subdividing test methods and it need to study constantly as varied angles.