• Journal of the Korean GEO-environmental Society
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• v.2 no.3
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• pp.71-80
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• 2001

The quantitative analysis of bearing capacity with stone column-mat is not ease because the bearing capacity of stone column is affected by so many parameters. The bearing capacity of stone column is mainly governed by horizontal resistance along the interface with soil. Also, this foundation system is affected by geometric factors such as column spacing, embedment ratio and failure surface inclination. Therefore, in this study, critical length and the effect of failure surface inclination was studied with single and group end bearing stone columns by loading tests. Results of model tests are compared to the present theoretical methods and are examined with FEM analysis.

• Journal of Technologic Dentistry
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• v.35 no.1
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• pp.29-35
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• 2013

Purpose: The purpose of this study was to evaluate the validity of digital models fabricated by dental scannable stone. Methods: Twenty same cases of stone models(maxillary full arch) were manufactured. Intercanine distance, intermolar distance, two dental arch lengths(right, left), two diagonal of dental arch lengths(right, left) were measured for comparison. Each of ten stone models were measured by digital vernier calipers and scanned by dental scanner. Ten digital models were measured by CAD program. The mean(SDs) values were compared by a Mann-Whitney U test(${\alpha}$=0.05). Results: No statistically significant differences between the two groups were found at intermolar distance, dental arch length(right)(p>0.05). However, intercanine distance, dental arch length(left) and two diagonal of dental arch lengths(right, left) were statistically significant(p<0.05). Conclusion: Stone models fabricated by dental scannable stone showed larger than digital models.

• Journal of the Korean Geophysical Society
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• v.7 no.1
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• pp.31-40
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• 2004

When surveying the cultural heritages especially in the case of stone structures, preserving their original state is of primary importance. For the effective assessment of survey results of stone structure, the dynamic characteristics of that system should be considered. Dynamic characteristics of stone masonry structures depend on several factors such as coefficients of friction, contact conditions, and number of layers of bonding stones. These factors can be estimated by using the dynamic analysis results. This paper describes a method for natural frequency determination of traditional stone arch bridge subjected to compressive force. For this purpose, multi-layered granite brick models of for arch bridge were made and fundamental frequencies corresponding increasing axial forces were measured.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.03a
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• pp.1378-1385
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• 2008

The probability of landslide hazards was predicted to natural terrain around the stone relics of Jinjeon-saji area, which is located in Yangyang, Kangwon Province. As the analysis results of field investigation, laboratory test and geology and geomorphology data, the effect factors of landslides occurrence were evaluated, and then the landslides prediction map was made up by use of prediction model considering the effect factors. The susceptibility of stone relics induced by landslides was investigated as the grading classification of occurrence probability using the landslides prediction map. In the landslides prediction map, the high probability area of landslides over 70% of occurrence probability was 3,489m3, which was 10.1% of total prediction area. If landslides are occurred at the high elevation area, the three stories stone pagoda of Jinjeon-saji (National treasure No.122) and the stone lantern of Jinjeon-saji (Treasure No.439) will be collapsed by debris flow.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2001.09a
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• pp.331-338
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• 2001

Seismic performances of the base isolated model of Five Story Stone Pagoda were studied through shaking table tests. Friction pendulum system (FPS), Pure-friction system with laminated rubber bearing (LRB) and Ball with rubber bearing were selected fur the comparison of performances. Performances of specially designed isolation systems were tested dynamically using shaking table. The test results of isolated model are compared with those of fixed base model. Compared with fixed base model, the isolated model showed that it could withstand much higer intensity of earthquake motion. The Effective Peak Ground Acceleration (EPGA) value of isolated model when the top component tipped over was above twice of that value in case of fixed base model. According to the additional test results, the lower value of coefficient of friction than that of common frictional base isolation systems is more effective to protect the piled multi-block system of Pagoda against moderate intesity of ground motion.

• Geomechanics and Engineering
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• v.13 no.2
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• pp.255-267
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• 2017

Soft clay strata can suffer significant settlement or stability problems under building loads. Among the methods proposed to strengthen weak soils is the application of a stone masonry trench (SMT) beneath RC strip foundations (as a masonry pad-stone). Although, SMTs are frequently employed in engineering practice; however, the effectiveness of SMTs on the ultimate bearing capacity improvement of a strip footing rested on a weak clay stratum has not been investigated quantitatively, yet. Therefore, the expected increase of bearing capacity of strip footings reinforced with SMTs is of interest and needs to be evaluated. This study presents a two-dimensional numerical model using the discrete element method (DEM) to capture the ultimate load-bearing capacity of a strip footing on a soft clay reinforced with a SMT. The developed DEM model was then used to perform a parametric study to investigate the effects of SMT geometry and properties on the footing bearing capacity with and without the presence of surcharge. The dimensions of the SMTs were varied to determine the optimum trench relative depth. The study showed that inclusion of a SMT of optimum dimension in a soft clay can improve the bearing capacity of a strip footing up to a factor of 3.5.

• Journal of The Korean Society of Agricultural Engineers
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• v.54 no.5
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• pp.103-111
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• 2012

In this study, the full-scale laboratory model test on utilization of recycled aggregates and crushed stone as vertical drains to use an alternative material of sand in soft ground is performed. The settlement and pore water pressure were measured to evaluate the discharge capacity and filed application, and the results were compared and analyzed through the finite element method. The measured and estimated settlement in all vertical drain materials decreases gradually with the load increase. The measured settlement 6.55~8.63 mm, and the estimated by the Hyperbolic model was 7.45~7.92 mm. So the model used for the analysis can be applied to the settlement estimation of the actual field. The variations of pore water pressure with time showed constantly regardless of the load in all vertical drainage materials. The pore water pressure was similarity to that of sand after rapid drawdown. Therefore, it was applicable to the field because discharge capacity was enough to be an alternative material to the sand which had been being used as the vertical drains.

• Journal of The Korean Society of Agricultural Engineers
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• v.52 no.6
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• pp.111-123
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• 2010

In this study, laboratory model test on utilization of recycled aggregates and crushed stone as horizontal drains to use alternative material of sand in soft ground is practiced. The coefficient of permeability of the recycled aggregates and crushed stone showed largely 1.2~5.1 times and 2.0~3.3 times greater than sand, respectively. The horizontal coefficient of permeability in case of installing the horizontal perforated drain pipe showed largely 1.9~6.8 times more than the case of not installing. The drainage distance showed 1.7~1.8 times greater than sand. When a degree of consolidation is 90 %, there is no delay of consolidation in SCP and PVD improvement sections. Therefore, it is proven that the field applicability is excellent. Also, the suitable quality management criterion is presented to make use of a horizontal drains in soft ground on the basis of analysis of the physical and environmental characteristics.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.1
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• pp.715-723
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• 2017

This study investigates the properties of a high-performance cementitious composite with partial substitution of stone dust for fine aggregate. The relationship between the properties and particle size distribution was analyzed using several analytical models. Experiments were carried out to examine the flowability, rheology, and strength of cement mortars with different stone-dust replacement ratios of 0-30 wt.%. The results showed improved flowability, lower rheological parameters (yield stress and plastic viscosity), and improved strength as the amount of stone dust increased. These results are closely related to the packing density of the solid particles in the mortar. The effect was therefore estimated by introducing an optimum particle size distribution (PSD) model for maximum packing density. The PSD with a higher amount of stone dust was closer to the optimum PSD, and the optimization was quantified using RMSE. The improvement in the PSD by the stone dust was proven to affect the flowability, strength, and plastic viscosity based on several relevant analytical models. The reduction in yield stress is related to the increase of the average particle diameter when using stone dust.

• Proceedings of the Korean Geotechical Society Conference
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• 2006.10a
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• pp.291-311
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• 2006

The acceleration of consolidation by stone columns was mostly analysed within the framework of a basic unit cell model (i.e. a cylindrical soil body around a column). A method of converting the axisymmetric unit cell into the equivalent plane-strain model would be required for two-dimensional numerical modelling of multi-column field applications. This paper proposes two practical simplified conversion methods to obtain the equivalent plane-strain model of the unit cell, and investigates their applicability to multi-column reinforced ground. In the first conversion method, the soil permeability is matched according to an analytical equation, whereas in the second method, the column width is matched based on the equivalence of column area. The validity of these methods is tested by comparison with the numerical results of unit-cell simulations and with the field data from an embankment case history. The results show that for the case of linear-elastic material modelling, both methods produce reasonably accurate long-term consolidation settlements, whereas for the case of elasto-plastic material modelling, the second method is preferable as the first one gives erroneously lower long-term settlements, where plastic yielding of stone column are ignored.