• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2005년도 지반공학 공동 학술발표회
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• pp.293-301
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• 2005

The CSG(Cemented Sand and Gravel) method is construction technique using as raw materials earth and gravel generated from a local construction site, mixing them with cement and rolling with vibration rollers. Recently, The use of this method for cofferdam and large dam is gradually increasing in Japan. The purpose of an CSG mix design is to develop project specific properties to meet the structure design requirements. But uniform mix design of CSG method has not yet been established. The experience of practitioners from the geotechnical and concrete disciplines has given rise to two genernal approaches to mix design for CSG. This paper reports the concept of how to set the mix design according to modified Proctor compaction test process and the test results on properties such as compaction, compressive strength and modulus of elasticity that obtained by unconfined compression test.

• 한국지반공학회논문집
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• 제20권8호
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• pp.41-48
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• 2004

이 연구에서는 아직 국내에서는 시공실적이 없는 쇄석다짐말뚝(Gravel Compaction pile)공법의 적용성을 판단하기 위하여 SCP와 GCP의 모형토조시험을 수행하였다. 즉, 원통형 압밀상자(지름 20cm, 높이 40cm)에 치환율 30, 40, 50, 60, 70%로 달리 조성하여 원심력 압밀시험기를 이용하여 압밀시킨 후, 재하시험을 통하여 두 공법의 지지력 특성을 비교 검토하였다. 또한 모형시험을 통해 얻어진 극한지지력을 기존에 제안된 SCP 및 GCP 시공지반의 극한지지력 산정식을 이용한 계산값과 비교하였다. 모형시험 결과 GCP 시공지반이 SCP 시공지반에 비해 지지력 측면에서 더 우수한 것으로 나타났다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2004년도 춘계학술발표회
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• pp.181-188
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• 2004

Composite soil methods among granular pile merhods that we could improve soft ground of fine soil particles by, have permeability as one of fundamental principals. The catual state, that voids of sand or gravel, etc. of granular soil as drainage materials are clogged by fine soil particles, is 'clogging'. In this study, it is analysed that using sand or gravel, etc. of granular soil as drainage materials, experiment are made by clogging tester on several condition.

• 한국지반환경공학회 논문집
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• 제19권5호
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• pp.13-22
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• 2018

The number of researches on the mechanical properties of cemented sand and gravel (CSG) materials and the application of the CSG Dam has been increased. In order to explain the technical scheme of strength prediction model about the artificial neural network, we obtained the sample data by orthogonal test using the PVA (Polyvinyl alcohol) fiber, different amount of cementing materials and age, and established the efficient evaluation and prediction system. Combined with the analysis about the importance of influence factors, the prediction accuracy was above 95%. This provides the scientific theory for the further application of CSG, and will also be the foundation to apply the artificial neural network theory further in water conservancy project for the future.

• 한국지형학회지
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• 제28권3호
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• pp.1-11
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• 2021

The drainage area of the Miho stream is composed of granitic basins, gneissic and sedimentary mountains. 80 percent of the Miho stream flows through the Jincheon basin and the Cheongju inner-plain within the Daebo granite belt. Because the deep weathering of granitic hills provides a large amount of sands to the streams, there are wide floodplains with thick alluvium developed in the basin and plain. The thickness of the alluvium is 5~10m and the width of the floodplains is 2~2.5km. In the basin outlet area where a stream passes through the mountain canyon, wide floodplains and deep alluvium are developed in other riverside. The Miho stream is a sand-gravel channel flowing through the Cheongju inner-plain with wide floodplains and deep alluvium formed by deep weathering of granite.

• 한국지반신소재학회논문집
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• 제22권3호
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• pp.1-10
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• 2023

최근 낙동강 하구에 많은 구조물이 건설되고 있으며 말뚝기초는 모래층 및 자갈층에 시공되고 있다. 이 연구에서는 낙동강 하구의 모래 자갈층 및 자갈층에 시공된 6개의 현장타설말뚝의 정재하시험 및 양방향재하시험 결과를 통해 비점성토층의 주면마찰력을 분석하였다. 또한 국·내외 설계기준인 FHWA(1999), KDS(2021), AIJ(2004)에 따라 계산된 주면마찰력과 실험값을 비교하였다. 6개 말뚝의 재하시험 결과를 통해 확인된 주면마찰력은 120~444kPa로 나타났다. 설계기준에 따라 산정한 주면마찰력은 69.3~170kPa이었으며 시험값 대비 50% 수준으로 나타났으며 이를 통해 설계기준들이 비점성토층에 근입된 현장타설말뚝의 주면마찰력을 상당히 보수적으로 평가하고 있음을 확인할 수 있었다. 국내 낙동강 하구 모래 자갈층 및 자갈층의 주면마찰력 산정을 위한 적절한 국내 제안식이 개발되어야 할 것으로 판단되었다.

• 한국지반환경공학회 논문집
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• 제7권4호
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• pp.43-52
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• 2006

최근 이상기후 및 집중호우로 인해 낙동강유역의 많은 지역이 재산 및 인명손실을 크게 입고 있다. 이러한 재해 대책의 일환으로 본 연구에서는 일본에서 본댐공사시 가물막이댐으로서 많이 활용하고 있는 CSG공법의 제방축조재료로서 적용성을 평가하기 위해 낙동강 유역의 하상재료인 빈입도의 모래를 시멘트와 혼합한 시멘트혼합토의 강도특성을 파악하고자 한다. 이를 위하여 낙동강유역 2지점의 모래와 시멘트의 혼합율을 2~8%까지 변화시키면서 다짐 및 CBR시험, 일축압축시험 그리고 중형삼축시험을 실시하여 시멘트혼합율과 재령에 따른 압축강도, 탄성계수, 그리고 변형에 따른 응력의 특성등을 검토함으로서 제체재료의 적합성 검토, 설계 및 해석에 필요한 기초자료를 제공하고자 한다.

• 한국철도학회논문집
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• 제9권4호
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• pp.493-498
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• 2006

In this study, two large pile load tests were performed in the deep sand gravel deposit of Nakdong river basin so that the characteristics of the load transfer was identified. The fully instrumented rectangular barrette pile in the size of $1.5\times3.0m$ and the circular bored pile of the diameter 1.5 m were placed into the ground below 50 m. Under the applied loads of 2,400 tonf and 4,000 tonf, the test results of the load transfer showed the portion of 83% and 93% of the applied loads on the barrette pile and the bored pile, respectively, were supported by the skin friction along the pile shaft. It was revealed that the most of these skin friction mobilized in sand layer underlying clay layer having N-value more than 30 and that the friction per unit area of the bored pile was larger than the friction of barrette pile. However, if embedded in the stiff sand graval layer, the both piles were proven to be sufficient for using as the friction piles.

• 자원환경지질
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• 제15권3호
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• pp.113-122
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• 1982

The surveyed Boseong river, flows from south to north crossing Boseong gun Mirukg myon, Nodong myon, Yuleo myon, Bocgnae myon, Mundeog myon, and Seungju gun Nam myon, Jeonranam do. The geology of the surveyed area consists of age-unknown composite gneiss and schist, crystaline chlorite gneiss, porphyroblastic gneiss and granite gneiss, and metasediments of Myon Bong formation and Seologri formation. These metamorphic rocks are intruded by cretaceous biotite granite, granodiorite, and quartz diorite. The heavy sands occur in Quarternary alluvium and colluvium. The composition of the river bed is sand 60%, gravel 30%, and clay 10%. The gravel content of the river bed decreases as the increases. The average depth of auger boring is 0.87 m. The average heavy mineral composition of the heavy sand is monazite 6.83%, zircon 4.88%, ilmenite 11.36%, magnetite 8.36% and garnet 4.84%. The best heavy minerals separation procedure would be primary treatment of the sand by humphrey spiral and table, and retreatment of the table concentrate by magnetic separator. The minimum economically feasible capacity of gravity and magnetic separation plant would be 500 ton/hr when only the heavy minerals are recovered but it may be reduced to 100 ton/hr. capacity, if gravels and sands are added to the valuable products.

• Geomechanics and Engineering
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• 제30권5호
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• pp.479-487
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• 2022

This study evaluates the performance of gravel impact compaction piers system (GICPs) in strengthening retrofitting a very loose silty sand layer with a very high liquefaction risk with a thickness of 3.5 meters in a multilayer coastal soil located in Bushehr, Iran. The liquefiable sandy soil layer was located on clay layers with moderate to very stiff relative consistency. Implementation of gravel impact compaction piers is a new generation of aggregate piers. After technical and economic evaluation of the site plan, out of 3 experimental distances of 1.8, 2 and 2.2 meters between compaction piers, the distance of 2.2 meters was selected as a winning option and the northern ring of the site was implemented with 1250 gravel impact compaction piers. Based on the results of the standard penetration test in the matrix soil around the piers showed that the amount of (N₁)₆₀ in compacted soils was in the range of 20-27 and on average 14 times the amount of (1-3) in the initial soil. Also, the relative density of the initial soil was increased from 25% to 63% after soil improvement. Also the safety factor of the improved soil is 1.5-1.7 times the minimum required according to the two risk levels in the design.