• Proceedings of the Korean Geotechical Society Conference
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• 2010.03a
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• pp.163-170
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• 2010

Today, In-Situ testing for measureing geotechnical characterization are divided by Cone Penetration Test, Standard Penetration Test and Dilatometer Test, and will vary depending on soil conditions have been applied (Korea Geotechnical Engineering, 2006). However, these methods can be applied on sand or soft clay soil. Now, many studies are progressing for evaluating the stiffness characteristic of rocks and IGM. and Nam moon suk(2006) did Texas Cone Penetrometer Test for designing field penetration pile intruded at rocks and IGM. but, reliability of Texas Cone Penetration Test has confidence limits because TCPT is testing in Texas centrally, and energy dose not measure Woojin Lee, etc. (1998) did calculate Standard Penetration Test Hammer's dynamic energy efficiency by using dongjaeha analyzer. this research, we installed strain gage and accelerometer for supply existing equipment, and develop MCP that can use variety soils. this thesis, we measured energy at head and tip of Rod for evaluating energy that transport at free falling. As a result, Energy differences are occurred at head and tip of Rod.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.03a
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• pp.349-360
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• 2009

The cone penetration test(CPT) has gained its popularity in site characterization indebted by its reliability, speed, economy, and automatic measurement system since its development in the 1930s. The CPT results, commonly consisting of cone tip resistance, sleeve friction, and pore water pressure measurements, allow us to classify soils as well as to reveal their engineering characteristics. The site condition at which the CPT is allowable is often dependent on the capacity of a CPT system. In Korea, it has been considered that the CPT could be appled only to soft soils in most cases because CPT systems available for stiff soils are very rare due to their expensive procurement and maintenance cost. Luoisiana Transportation Research Center(LTRC) has developed and implemented a field-rugged continuous intrusion miniature cone penetration test(CIMCPT) system since the late 1990s. The miniature cone penetrometer has a sectional cone area of $2cm^2$ allowing system capacity reduction compared to the standard $10cm^2$ cone penetrometer. The continuous intrusion mechanism allows fast and economic site investigation. Samsung Engineering & Construction has recently developed and implemented a similar CIMCPT system based on its original version developed in LTRC. The performance of the Samsung CIMCPT system has been investigated by calibration with the standard CPT system at a well-characterized test site in Pusan, Korea. In addition, scale effect between the miniature cone penetrometer and the standard cone penetrometer has been investigated by comparing the field test results using the both systems.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.267-272
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• 2003

In order to investigate the effect of face material on Ti/Al alloy laminates under high velocity impact, a ballistic testing was conducted. Ballistic resistance of these materials was measured by protection ballistic limit($V_{50}$), a statistical velocity with 50% probability penetration. Fracture behaviors and ballistic tolerance, described by penetration modes, were respectfully observed, by $V_{50}$ test and Projectile Through Plates (PTP) test at velocities greater than $V_{50}$. PTP tests were conducted with $0^{\circ}$obliquity at room temperature using 5.56mm ball projectile. $V_{50}$ tests with $0^{\circ}$obliquity were also done with projectiles that were able to achieve near or complete penetration during PTP tests. Resistance to penetration, and penetration modes which face material was Titanium alloy, were compared to those which face material was anodized Al alloy after cold-rolling.

• International Journal of Precision Engineering and Manufacturing
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• v.4 no.4
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• pp.45-50
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• 2003

In order to investigate the effect of surface treatment (Anodizing) and rolling on AI 5083-H131 alloy, under hyper velocity impact, a ballistic testing was conducted. Ballistic resistance of these materials was measured by a protection ballistic limit ($V_{50}$)' a statistical velocity with 50% probability of penetration. Perforation behavior and ballistic tolerance, described by penetration modes, were respectfully observed, by $V_{50}$ test and Projectile Through Plates (PTP) test at velocities greater than $V_{50}$. PTP tests were conducted with 0$^{\circ}$ obliquity at room temperature using 5.56mm ball projectiles. $V_{50}$ tests with 0$^{\circ}$ obliquity were also done with projectiles that were able to achieve near or complete penetration during PTP tests. Resistance to penetration, and penetration modes of Al 5052-H34 alloy were compared to those of Al 5083-H 131 alloy.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.12
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• pp.126-134
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• 2003

In order to investigate the effect of surface treatment in Aluminium alloy and Titanium alloy which are used to armor material during ballistic impact, a ballistic testing was conducted. Anodizing was used to achieve higher surface hardness of Aluminium alloy and Iron plating in PVD(Physical Vapor Deposition) method was used to achieve higher surface hardness of Titanium alloy. Surface hardness test were conducted using a Micro victor's hardness tester. Ballistic resistance of these materials was measured by protection ballistic limit(V-50), a statical velocity with 50% probability penetration. Fracture behaviors and ballistic tolerance, described by penetration modes, are respectfully observed from the results of V-50 test and Projectile Through Plates (PTP) test at velocities greater than V-50. PTP tests were conducted with 0$^{\circ}$obliquity at room temperature using 5.56mm ball projectile. V-50 tests were conducted with 0$^{\circ}$obliquity at room temperature with projectiles that were able to achieve near or complete penetration during PTP tests. Surface hardness, resistance to penetration. and penetration modes of surface treated alloy laminates are compared to those of surface non-treated alloy laminates. A high speed photography was used to analyze the dynamic perforation phenomena of the test materials.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.11a
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• pp.125-128
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• 2004

This study concerns the new estimated strength equation of concrete by penetration test. There are not only few estimate strength equations of concrete, but also many problems to apply them because of time, cost, easiness, structural damage, reliability and so on. In this study, there performed a series of penetration test with in 730days' concrete structures and proposed equations as follows; $$Linear\;:\;f_{ck}=2.95d-80.0(r^2= 69.8\%)$$ $$Quadratic\;:\;f_{ck}=0.204d^2-12.15d+193.2(r^2=83.6\%)$$ here, fck : Estimated compressive strength of concrete by MPa d: exposed probe length by mm.

• Journal of the Korean Geotechnical Society
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• v.32 no.10
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• pp.5-15
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• 2016

This study investigated both water content and penetration resistance of small cone of various clay soils that were made of Kaolinite and Bentonite with different mixing ratios and compared the results with those of the existing dynamic (Casagrande test) and static (fall cone test) tests directly. The comparison showed that the water content at the inflection point on a curve of water content and penetration resistance was very similar to the liquid limit from a fall cone test. The penetration resistance of small cone at the inflection point was 0.2 kPa, and it was ascertained that the water content at the inflection point represents a liquid limit of clay soils. From the study results, it was found that the penetration resistance of 0.2 kPa with the small cone can be an indicator of the liquid limit of clay soils in practice. Finally a test procedure to measure the liquid limit of clay soil based on a penetration resistance of small cone was proposed.

• 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.

• Journal of the Korean Geotechnical Society
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• v.36 no.12
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• pp.35-43
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• 2020

Currently, cofferdams of circular cross section are widely applied as temporary facilities for the installation of bridge foundations in river/sea bridge construction in Korea. Existing caisson, sheet pile, and cell type cofferdam are widely used, but these methods take a lot of time and cost for installation and dismantling. In the case of the existing sheet pile construction method, attention is needed to secure internal and external stability because of the damage to the sheet pile due to ground penetration and difficulty in connecting element members. In this study, penetration design of circular steel pipes using suction pressure was performed on the soft ground of the west coast, and it was confirmed that penetration construction using suction pressure was possible through field tests. It was confirmed that applying the ground analysis results using the cone penetration test (CPT) to the design rather than the standard penetration test (N value) results more similar to the field test results. In addition, it was confirmed that local failure of the inside of the cofferdam was induced when a suction pressure higher than the upper limit suction pressure was applied in the silty sand.

• 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.