• Journal of the Korean Geotechnical Society
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• v.23 no.12
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• pp.5-11
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• 2007

Among soft ground improvement methods by using granular material, the sand compaction pile method has been widely utilized in Korea, but, as a result of shortage and increase of unit price of sand, a necessity of an alternative method has been required. In this study, a series of in-situ static load tests for crushed-stone compaction piles were performed. Pile diameter was fixed to 700mm and areas of loading plates were changed. The static load tests were performed for area replacement ratios of 20, 30 and 40% respectively. Based on the test results, bearing capacity of single crushed-stone compaction pile was estimated. It showed that the settlement decreases as the replacement ratio increases. Also, a yielding capacity equation of the crushed-stone compaction pile considering replacement ratio was suggested.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.03a
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• pp.747-754
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• 2010

The objective of this study is improve the technology by various testing devices for measuring degree of compaction. The methods for quality control for compaction are very various. But, normally the specifications have provided PBT(Plate Bearing Test) method when inspector tested quality control. In spite of the PBT has a few weak points to reduce process and cost. In order to improve quality control method, analyzed in-situ test results between PBT and other devices.(LWDT and Geogauge).

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.507-514
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• 2005

In this construction case study, Crushed stone under 100mm diameter was carried out a test compacted construction for subgrade in the 3rd. runway of the 2th Incheon International Airport Construction area. Conforming to specification needs a minimum rolling compacted number 10 for upper subgrade 100% compaction degree indicated in Federal Aviation Administration and $K_{30}{\geq}20kgf/cm^3$ in plate bearing test. $K_{30}$ to be acquired 100% compaction degree of upper subgrade is confirmed to about $31kgf/cm^3$ from correlation $K_{30}$ vs relative compaction degree.

• Journal of the Korean Geotechnical Society
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• v.36 no.12
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• pp.45-56
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• 2020

In this paper, intelligent compaction (IC) technology and the earthwork quality control specifications based on IC were analyzed, and the field study was conducted to investigate the relationship between the representative IC value CMV (Compaction Meter Value) and spot test results (plate bearing test and field density test). As the number of roller passes increased, both the CMV and spot test results increased. However, point-by-point comparison between CMV and spot test results yielded poor quality correlations; this is because the ununiform stiffness of the underlying layer and the moisture content of the lift layer affected the CMV and spot test results, respectively. Most international specifications related to IC requires knowledge of the IC values and their relationships with the soil properties obtained by the traditional spot tests. Therefore, for the successful implementation of intelligent compaction technology into earthwork construction practice, the number of roller passes as well as the lift thickness and the moisture content of the soil should be carefully considered.

• International Journal of Highway Engineering
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• v.7 no.4 s.26
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• pp.31-39
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• 2005

Tests are conducted to analyze the compaction characteristics of domestic river sand used frequently for backfill in construction of electrical pipeline. As a result of test, the range of specific gravity of sand is found to be in between 2.63 and 2.67, and of maximum dry weight of sand is in between $1.70g/cm^3\;and\;1.86g/cm^3$. Also, the optimum moisture content is found to be in between 11.3% and 13.8%. The variability of compaction degree with respect to compaction energy is well captured by hyperbolic function.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.705-712
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• 2005

Among soft ground treatment methods with granular soil used in domestic, the sand compaction pile method has been utilized greatly, but, as a result of exhaustion of sand and increase of unit cost, a necessity of an alternative method is suggested. In this study, the static load tests for group crushed-stone compaction piles which were constructed at in-situ site were performed. Pile diameter was 700mm and area of loading plates were changed. The static load tests of single and group piles were performed for area replacement ratio of 20, 30 and 40%. Based on test results, bearing capacity of group crushed-stone compaction pile were estimated. The more both single pile and group pile increase, the more yield bearing capacity tended to increase. Also, the yield bearing capacity of a group pile is about 50% less than the yield bearing capacity of a single pile. If the ground reinforced with the crushed-stone compaction pile is replacement ratio of $20{\sim}40%$, RIYB of both single pile and group pile increases qualitative tendency of linear more than original ground

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.286-293
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• 2005

In soft ground the settlement criterion usually governs. Therefore, it is very important not only reasonable assessment of the allowable bearing capacity of the soil but also reasonable assessment of settlement. In the previous studies by many other researchers, load concentration ratio and settlement reduction factor are usually proposed for estimating the settlement of granular compaction piles. In the previous studies, the reinforced ground with granular compaction piles is simplified as composite ground and the analysis is performed with in the basis of this assumption. However, the lateral deformation of granular compaction pile could not be considered and only the relative vertical strength between pile and soils could be considered in the analysis. In this study, a method adapting the Tresca failure criterion is proposed for calculating settlement of granular compaction pile. Proposed method can be considered the strength of pile material, pile diameter, installing distance of pile and the deformation behavior of vertical and horizontal directions of pile. In the presented study, large-scale field load test is performed and the results are described. Also, predictions of settlements from the proposed method are compared with the results of the load test. In addition, a series of parametric study is performed and the design parameters are analyzed.

• Journal of the Korean Geotechnical Society
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• v.34 no.6
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• pp.37-47
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• 2018

In this study, 34 laboratory load test data were collected, and analyzed to propose the equations for predicting ultimate bearing capacity of sand compaction pile (SCP) and gravel compaction pile (GCP) reinforced clay. The collected data were compared with the ultimate bearing capacity estimated by existing theoretical equations, and the prediction accuracy of the existing theoretical equations was identified. Also, multiple regression analysis was performed to predict the ultimate bearing capacity, and the most efficient number and type of input variables were selected through error evaluation by leave-one-out cross validation. Finally, the multiple regression equations for estimating the ultimate bearing capacity of laboratory load test for SCP and GCP were proposed, and their performance was evaluated.

• Journal of the Korean Geotechnical Society
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• v.15 no.1
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• pp.41-52
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• 1999

In order to assess the quality and depth of ground densification by compaction, SPT and/or CPT are performed before and after compaction. Both methods are intrusive and one point tests, require a substantial time to evaluate a large area, and their results are quite dependent on the operation technique and soil type. In this paper, the quality and extent of ground densification by compaction was evaluated by using in situ SASW test and laboratory resonant column (RC) test results. SASW test was used to determine the shear wave velocity profiles before and after compaction, and RC test was adopted to determine the correlation between the normalized shear wave velocity and the density of the site, which is almost uniquely independent of confinement. Testing and data reduction procedures of both tests were discussed, and a simplified evaluation procedure of ground densification was proposed. Finally, the feasibility of the proposed method was verified by performing field study at Inchon International Airport Project. Field densities determined by the proposed method matched well with those determined by sand cone tests.

• Journal of Powder Materials
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• v.21 no.1
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• pp.44-49
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• 2014

In this study, nanocrystalline nickel powders were cold compacted by a dynamic compaction method using a single-stage gas gun system. A bending test was conducted to measure the bonding strengths of the compacted regions and microstructures of the specimen were analyzed using a scanning electron microscopy. The specimen was separated into two parts by a horizontal crack after compaction. Density test shows that the powder compaction occurred only in the upper part of the specimen. Brittle fracture was occurred during the bending test of the compact sample. Dispersion of shock energy due to spalling highly affected the bonding status of the nanocrystalline nickel powder.