• Journal of the Korean GEO-environmental Society
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• v.8 no.3
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• pp.19-25
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• 2007

Stone columns is the ground improvement method which composed of compacted gravel or crushed stone inserted into the soft ground consisting of loose sand and clay. There are many difficulties in quantitative analysis of soil-pile interaction because settlement behavior of stone columns is affected by various parameters. In this study, various parameters of behavior of end-bearing group piles are investigated by load tests. Finally, the improved characteristics of soft ground and the influence of design parameters are investigated in this study using PR (performance ratio) value. From the PR value calculation and test results, we know that settlement behavior of stone columns is affected by area replacement ratio of composite ground, diameter of column rather than embedment ratio and mat.

• Geotechnical Engineering
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• v.9 no.3
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• pp.35-48
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• 1993

This paper was focused on the design and construction of stone columns as a method of reinforcements in slightly soft clay or loose silty sand overlying the firm strata. It was intended to find out the effects of soil improvement by field tests in Kwangmyoung Haan Site by comparing the test results performed before and after the installation of stone columns . The results of this experimental study are as follows : the hearing capacity was increased by 3.33 times and the SPT N -valued was increased by 3.9 times by installing the stone columns : the stone column method can cut down the construction cost almost 35% compared to the precast concrete pile method in economic viewpoints.

• Journal of the Korean Geosynthetics Society
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• v.10 no.4
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• pp.123-130
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• 2011

In the precedent study it was presented that the comparison of thermal resistivity using various backfill materials including river sand regarding water content, dry unit weight and particle size distribution. Based on the precedent study, this study focused on developing the optimized backfill material that would improve the power transfer capability and minimize the thermal runaway due to an increase of power transmission capacity of underground power cables. When raw materials, such as river sand, recycled sand, crush rock and stone powder, are used for a backfill material, they has not efficient thermal resistivity around underground power cables. Thus, laboratory tests are performed by mixing Fly-ash, slag and floc with them, and then it is found that the optimized backfill material are required proper water content and maximum density. Through various experimental test, when coarse material, crush rock, is mixed with recycled sand, stone powder, slag or floc for a dense material, the thermal resistivity of it has $50^{\circ}C$-cm/Watt at optimum moisture content, and the increase of thermal resistivity does not happen in dry condition. The result of experiments approach the optimization of the backfill materials for underground power cables.

• Economic and Environmental Geology
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• v.33 no.2
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• pp.139-146
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• 2000

Development of an effective liner by utilization of the tailings frm the Imcheon mine and polymer has been tried. The tailings piled in the Imcheon mine, whose true specific gravity is about 2.86, are composed mainly of quartz, alkali-feldspar, muscovite and pyrite, and mostly (93.7% in volume) coarser than sand grain size (50${\mu}{\textrm}{m}$). Strength, leaching and permeability tests have been performed on the test specimens of polymer concrete manufactured with various mixing proportions of tailings, unsaturated polyester resins(UPR), calcium carbonates, stone powder sludges and granite soils. Polymer concrete specimens with stone powder sludges or granite soils as fillers and aggregates indicate 2.5 to 3 fold higher flexural and compressive strengths and lower permeabilities than those with calcium carbonates, which shows their usability as a waterproof liner. Also, the polymer concrete liner with stone powder sludge fillers is more advisable in aspects of utilization of waste sludges than that with other fillers.

• Proceedings of the Korean Geotechical Society Conference
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• 2001.03a
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• pp.299-306
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• 2001

Crushed Stone Pile(CSP) is one of the ground improvement methods available to loose sand and clayey ground by forming compacted CSP in the weak soil layer. The effects of this method are enhancement of ground bearing capacity, reduction of settlement and prevention of lateral ground movement in cohesive layer, reduction of liquefaction potential in sandy ground. This study performs model tests in 1.0m${\times}$1.0m${\times}$1.0m and 1.5m${\times}$1.5m${\times}$l.2m model tank to observe bearing capacity of CSP treated ground. The area replacement ratio of CSP composite ground varies 20%, 30% and 40% with square grid pattern. After the composite ground was consolidated under pressure of 0.5kg/$\textrm{cm}^2$ and 1.0kg/$\textrm{cm}^2$, load tests were carried out. The results show that ultimate bearing capacity increases with area replacement ratio and the preconsolidation pressure of ground.

• Magazine of the Korean Society of Agricultural Engineers
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• v.44 no.2
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• pp.107-116
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• 2002

The amount used of aggregates for concrete is increasing rapidly since the mid-1980s in Korea. The natural gravels from river are already displaced with crushed stone, and use of crushed sand as a substitute of natural river sands, also, is getting increased day by day. This paper is presented fur analysis on mechanical properties of high strength concrete using fly ash and crushed sand. The material functions in mixing design of concretes are various water-cement ratios(w/c) such as 0.25, 0.40, 0.55 and different replacement ratio of crushed sand to natural sands such as 0%, 20%, 40%, 60%. As a results, it has been shown that compressive strengths of concretes with W/C lower than 0.40 and 0.25 are higher than 400 kgf/$\textrm{cm}^2$ and 600 kgf/$\textrm{cm}^2$ respectively. It is also concluded that the results of rapid chloride permeability tests of concrete are evaluated to negligible. The conclusions of this study is that it is possible to use fly ash and crushed sand fur high strength concrete.

• Proceedings of the Costume Culture Conference
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• 2003.12a
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• pp.21-26
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• 2003

I 의류의 염색 및 가공 1. 염색 방법 (섬유제품에 의한 분류) ① 섬유 염색 (Fiber Dyeing) ②사염 ③ 원단 염색 ④ 의류 염색 2. 염료 종류에 따른 염색 (Cellulose 섬유를 중심으로) ① 직접 염료에 의한 염색 ② 반응성 염료에 의한 염색 ③ VAT 염료에 의한 염색 ④ Pigment Dyeing ⑤ 형광 증백제에 의한 염색 3. Washing 가공 ① Normal Washing ② Stone Washing ③ Bio Washing ④ Acid Washing ⑤ Sand Washing (중략)

• Journal of the Korean GEO-environmental Society
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• v.1 no.1
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• pp.27-33
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• 2000

Stone columns is ground improvement method which is composed of compacted gravel or crushed stone inserted into the soft ground consisting of loose sand and clay by replacement method. Generally stone columns are constructed in silty clay, above 70% replacement rate for increasing the bearing capacity and shear strength. Low replacement stone columns method is limited below 30% at replacement rate-premising strength increase of clay ground is estimated efficiently. This study, laboratory model tests were conducted to investigate the consolidation drainage promotion and shear strength increase effect in soft ground with replacement rate by stone columns. The settlement reduction effect and settlement reduction coefficients increase with increasing the replacement rate in composite ground. The results of model tests indicate that consolidation promotion effect is proved. The increasing strength of composite ground was verified by vane shear tests.

• Journal of the Korean GEO-environmental Society
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• v.17 no.3
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• pp.5-12
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• 2016

Stone column is the method that replace soft ground such as weak clay and loose sand with gravel or crushed stone which has relatively high stiffness and low compressive. Stone column increases bearing capacity of the soft ground, reduces settlement, produces ground improvement effect by consolidation drain, and is effective to prevent soil liquefaction in sandy ground during an earthquake. Stone column has been used in many civil works, and has recorded quite a lot of construction achievement internationally, but there is no standardized settlement calculation method yet. Therefore, in this study, the applicability of the existing theoretical equations were evaluated through comparison and analysis to predict a reasonable settlement of the Stone column. Consequently, Hook's law formula was verified to be the most close to numerical analysis.

• The Journal of the Convergence on Culture Technology
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• v.9 no.1
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• pp.711-716
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• 2023

A large amount of stone is required as a high-end strategy for building new construction and remodeling work, and aggregates have to be collected from many stone mountains due to the lack of river sand and gravel required for concrete production. This study examines the case of development of stone materials for construction, conduct and analyze residents' attitudes, find out residents' thoughts on stone mountain development, develops the area as an alternative to the devastation caused by stone mountain development, and recycles it as an efficient resource. We intend to conduct basic research to propose a plan. As a result, Local residents have a lot of antipathy against the use of quarry, so it is necessary to use the area that is far from the residents' areas as a quarry. It was concluded that it was desirable to restore and develop in the right direction.