• Journal of the Korean Geotechnical Society
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• v.17 no.6
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• pp.85-98
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• 2001

Cone penetration was analyzed by arbitrary Lagangian-Eulerian(ALE) method. In order to simulate full penetration, steady state analyses were performed using ABAQUS/Explicit, which models upward flow of soil layers. In the analysis of homogeneous layer it was found that the paths and the strain of soil particles were consistent with the result of the strain path method and that the ultimate resistance were reasonably evaluated. The cone penetration through different soil layers was also analyzed and that showed the transfer of cone resistance. The steady state ALE analysis could perform full penetration through the layered soils.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.09a
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• pp.1407-1414
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• 2009

In this study, a Jeju sand, which contains both siliceous and calcareous materials, was sampled from a beach in Jeju Island. It is observed that the Jeju sand has high extreme void ratios due to the angularity of grains and the intra-particle voids of hollow particles. From cone penetration test using calibration chamber system, it is found that the cone tip resistance($q_c$)-relative density(Dr)-vertical effective stress(${\sigma_v}'$) relation of Jeju sand almost matches to that of high compressible quartz sand. However, this correlation overestimates the relative density of a coastal sediments in Jeju Island maybe due to the cementation effect of this area. From analysis of the results of cone penetration and SPS tests at a coastal area in Jeju Island, it seems reasonable to assume that the coast of Jeju Island is a natural cemented sediments.

• Geotechnical Engineering
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• v.3 no.2
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• pp.17-28
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• 1987

Reliability of the cone penetration test (CPT) for estimating shear strength of marine soils is investigated in this paper. For sands, the uncertainty about the angle of internal friction is analyzed. It includes the spatial variation of the soil and the model error in the equation used for interpretation. The most serious uncertainty encountered was the error in the interpretative models. Different methods of interpretation gave quite different values. Subjective opinion was introduced to combine all the interpretative models in a systematic manner. For clays, the undrained Shear Strength from the CPT results is usually =derived by empirical correlations between cone resistance and untrained shear strength from laboratory tests or field vane tests, expressed in terms of cone factor and function of overburden pressure. The uncertainty of the undrained shear strength is caused by data scatter of the cone factor in the correlation, model error of the cone factor, effect of anisotropy, and spatial variability of cone resistance. Among these uncertainties, the most serious one was the data scatter of the cone factor in the .correlation. Between the laboratory test and the field vane test used for correlation, the field vane test was more reliable.

• Polymer(Korea)
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• v.24 no.6
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• pp.777-786
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• 2000

Fire resistance and thermal stability of polypropylene composite systems were investigated by using several halogenated fire-retardants such as decabromodiphenyl oxide (DBDPO) and chlorinated paraffin wax (CPW). The fire resistance of composite systems was thoroughly examined by measuring limited oxygen index (LOI, ASTM D2863, ISO 4589) and characteristic properties of cone calorimetry(ASTM E1354, ISO 5660) heat release rates (HRR), time to ignition (TTI), total heat release (THR), effective heat of combustion (EHC), mass loss rates, etc. Comparing the cone calorimetry experimental results of the halogen flame retardants, DBDPO exhibited twice higher efficiency than CPW in polypropylene systems, and the LOI also showed similar trends to cone calorimetry. The thermo-oxidative stability of the composite systems was increased about 30-5$0^{\circ}C$ in thermogravimetry analysis.Collectively, the combustion, extinction and thermally-stable characteristics of flame retardants were identified in this study.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.2
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• pp.631-642
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• 2013

The standard CPT(Cone Penetration Test), which can be easily performed to investigate in-situ soil engineering properties, has been widely used. CPT are also widely being utilized in centrifuge model tests. In this study, a miniature cone with 10mm diameter was developed and its applicability in the centrifuge was evaluated. The developed miniature cone was equipped with a four degree-of-freedom in-flight robot. A series of cone penetration tests was performed under four centrifuge acceleration levels. As results, the cone resistances measured at the same confining stress within shallow penetration depth were affected by the centrifugal accelerations. The critical depth was proportional to the cone diameter and relative density. Cone resistances results below the critical depth and soil parameters obtained from the laboratory tests were compared with those by previously proposed empirical relations.

• Geomechanics and Engineering
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• v.23 no.6
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• pp.523-533
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• 2020

The current study focuses on the effect of the end shape of steel pipe piles on installation effort and bearing resistance using the pressing method of installation under dense ground conditions. The effect of pile rotation on the installation effort and bearing resistance is also investigated. The model steel piles with a flat end, cone end and cutting-edge end were used in this study. The test results indicated that cone end pile with the pressing method of installation required the least installation effort (load) and showed higher ultimate resistance than flat and cutting-edge end piles. However, pressing and rotation during cutting-edge end pile installation considerably reduces the installation effort (load and torque) if pile penetration in one rotation equal to the cutting-edge depth. Inclusion of rotation during pile installation reduces the ultimate bearing resistance. However, if penetration of the cutting-edge end pile equal to the cutting-edge depth in one rotation, the reduction in ultimate resistance can be minimized. In comparing the cone and cutting-edge end piles installed with pressing and rotation, the least installation effort is observed in the cutting-edge end pile installed with penetration rate equal to the cutting-edge depth per rotation.

• The Journal of Engineering Geology
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• v.8 no.1
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• pp.25-34
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• 1998

It is not easy to understand exact soil properties, because soil is nonhomogeneous and anisotropic. There are raany inefficient cases in aspect of time and economy in site survey. So this study tried to analyze the correlation of cone resistance and seismic velocity in order to present an efficient method in ground investigation. A cone penetrometer is frequently used to investigate soil properties, which are especially fit to investigate coastal soft ground. A portable cone penetrometer was used in this research. A portable cone penetrometer has an advantage in investigating the state of soil swiftly and is convenient to manipulate. Also, seismic prospecting is one of the most PoPular methods among geophysical prospecting methods in the estimation of ground properties and its usage is continuously increasing in the survey of soft ground Cone resistance makes a regular group according to stratum in each depth. The results of seismic prospecting show a tendency to have a certain coherence according to the boundary of straturft Therefore, cone resistance and seisrnic prospecting have considerable relations that rnay irnprnve the efficiency of ground investigation.

• Journal of the Korean Geotechnical Society
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• v.22 no.10
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• pp.55-67
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• 2006

Modern methods for designing IGM(Intermediate Geomaterial) socketed drilled shafts require knowledge of the compressive strength and modulus of the IGM. However, the weathered IGMs at many sites prohibit the recovery of samples of sufficient length and integrity to test cores in either unconfined or triaxial compression tests. Since rational design procedures usually require values of compressive strength, surrogate methods must be employed to estimate the compressive strength of the IGM. A surrogate method considered in this study was Texas cone penetrometer tests which were performed at several sites in North Central Texas. Correlations of Texas cone penetrometer tests and compressive strengths of cores from these formations are provided in the paper. In order to develop the relationships between Texas cone penetrations and side and base resistance of IGM socketed drilled shafts, three filed load tests were conducted in the same sites. Based on the field study and literature reviews, a design method for IGM socketed drilled shafts using Texas cone penetration test was proposed.

• Journal of the Korean Geotechnical Society
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• v.27 no.2
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• pp.43-52
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• 2011

The characteristics of shear zone in granular soils largely affect the stability of geo-structures. The goal of this study is to evaluate shear zone in a direct shear test using shear wave, electrical resistivity, and cone tip resistance. Bender elements and electrical resistivity probe are embedded into the wall of a direct shear box made of transparent acrylic material to estimate the shear wave velocities and the electrical resistivity at shear and non-shear zones. At the point of peak and residual strength, micro cone penetration test which can be available to measure tip resistance has been performed. Experimental results show that the shear wave velocities at upper shear zone increase during shearing while the values remain constant at bottom and lower shear zone. Also, resistivities at lower shear zone depend on relative density while resistivities at bottom remain constant. The results of cone penetration test demonstrate the correlation of the cone tip resistance and small strain shear modulus at shear zone. This study suggests that the application of the modified direct shear box including shear wave, electrical resistivity and the micro cone tip resistance may become effective tools for analyzing the characteristics of a shear zone.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2015.11a
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• pp.158-159
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• 2015

Architectural fabrics are now used in membrane structure with the merits of free shape, lightness and opened up new possibility for the design of new building structures. Recently PVC, PVF, PVDF, PTFE coated fabric for using the membrane structures. However, clear standards for the design and construction is not exist because of the lack of Architectural fabric research. In this paper, Flammable properties of PVDF, PTFE coated fabrics are obtained through the Flammability test using the Cone Calorimeter. Based on these results, identify the fire resistance property of the Architectural fabric.