• 대한토목학회논문집
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• 제28권3B호
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• pp.315-321
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• 2008

최근 해안환경적 측면 뿐 만 아니라 사용자의 측면에서 도류제나 방파제와 같은 연안구조물에 의하지 않고 연안에서의 해빈을 보존하기 위한 대책이 요구되고 있다. 연안에서의 표사문제의 대책을 수립하기 위해서는 연안에서의 표사 뿐만 아니라 배후지의 하천으로부터 유출되는 유사량을 포함한 종합적인 토사관리의 필요성이 증가하고 있다. 이같은 관점에서 본 연구에서는 연안해역으로 유출되는 하천 유사와 이송, 하구에서의 사주발생과 발달 그리고 하구폐색과 연안으로 유출된 유사의 효율적인 저류문제와 홍수시 외해로 유출되는 유사의 특성에 대해 검토하였다. 최근 강릉 남대천 하구에는 하구폐색과 하구사주의 발생에 따른 대책으로 2005년에 총연장 260 m의 도류제를 건설하였다. 이에따라 본 연구에서는 도류제 건설에 따른 남대천하구에서의 토사이동특성 및 해저지형 변동과 표사이동을 해석하기 위한 다양한 수치실험을 수행하였다. 이를 위해 먼저 남대천 하구역에서 유출되는 유사량을 혼합입경의 관점을 가정하여 1차원 수치해석을 통하여 해석하였다. 또한 하천에서 유출된 유사의 이동특성과 하구현상을 파악하기 위해 하천류의 유동특성과 바람장에 의한 취송류를 검토하였다. 그리고 파동장, 해빈류 및 해저지형변동을 수립하여 본 남대천 하구인근에서의 표사이동 특성을 해석하였다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 1999년도 봄 학술발표회 논문집
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• pp.489-496
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• 1999

The objective of this study is to present engineering properties required in use of co-mixtures of fly ash and WFS(Waste Foundry Sand)'s, which are Presently used as fill or (lovable backfill. The fly ash, generated at the Tae-An thermoelectric power plant was used in this research and was classified as Class F. Green Sand, Furane Sand, and Coated Sand, which had been used at a foundry located in Pusan, were used. Laboratory experiments were peformed to obtain the physical properties of the co-mixture of fly ash and WFS. The range of permeability for all the co-mixtures was from 3.0×10/sup -3/㎝/s to 6.0×10/sup -5/㎝/s. The unconfined strength of the 7-day cured specimens composed of Green Sand reached 94% of that of 28-day cured specimens but for the 7-day cured specimens composed of, respectively, Furnace Sand and Coated Sand, only 64% and 66% of the strength of the 28-day cured specimens were reached. Results of the consolidated-untrained triaxial test showed that the specimens composed of Furnace Sand showed a distinct increase of the internal friction angle, while the other specimens showed negligible increase. In the case of 28-day cured specimens, specimens composed of Furnace Sand showed an internal friction angle of 41.8°, while specimens of Green and Coated Sand showed those of 33.5° and 35.0°, respectively. From the shrinkage test, the shrinkage ratios of all specimens did not exceed 0.25%.

• Geomechanics and Engineering
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• 제10권4호
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• pp.455-470
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• 2016

In ballasted railway tracks, ballast fouling due to finer material intrusion has been identified as a challenging issue in track maintenance works. In this research, deformation characteristics of crushed stone-sand mixtures, simulating fresh and fouled ballasts were studied from laboratory and a 3-D discrete element method (DEM) triaxial compression tests. The DEM simulation was performed using a recently developed DEM approach, named, Yet Another Dynamic Engine (YADE). First, void ratio characteristics of crushed stone-sand mixtures were studied. Then, triaxial compression tests were conducted on specimens with 80 and 50% of relative densities simulating dense and loose states respectively. Initial DEM simulations were conducted using sphere particles. As stress-strain behaviour of crushed stone-sand mixtures evaluated by sphere particles were different from laboratory specimens, in next DEM simulations, the particles were modeled by a clump particle. The clump shape was selected using shape indexes of the actual particles evaluated by an image analysis. It was observed that the packing behaviour of laboratory crushed stone-sand mixtures were matched well with the DEM simulation with clump particles. The results also showed that the strength properties of crushed stone deteriorate when they are mixed by 30% or more of sand, specially under dense state. The results also showed that clump particles give closer stress-strain behaviour to laboratory specimens than sphere particles.

• KIEAE Journal
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• 제9권2호
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• pp.65-71
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• 2009

Results from tests for what mixing rate of soil and sand is proper for the rammed earth and for how much additives are optimum are as under. 1) In the test to evaluate what mixing rate of soil and sand is desirable, peptizing property and surface sticking rate are found similar in its degree, but compression strength is found most stable when the ratio of soil and sand mixing shows 30:70 which indicates the best mixing rate of soil and sand. 2) In a test to add hydrated lime, compression strength, peptizing property, and surface sticking rate are found best when the mixing rate of soil and sand shows 23:7. 3) In a test to add sea weeds, the peptizing property goes down at 75% of sea weeds input a little bit more than at 100%, but compression strength shows best at 75% which is thought to be the best rate. 4) In a drop test, more soil powder mixed, the sticking strength gets better and more sands are contained, the sticking strength gets far worse to be scattered in powder type. 5) As concluding all results mentioned in the above item, the most desirable mixing rate of soil, sand, and hydrated lime is found to be 23:7:70 for the rammed earth where compression strength, peptizing property, and surface sticking rate are best.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2012년도 춘계 학술논문 발표대회
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• pp.77-79
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• 2012

This study is to assess the differences between concrete having only one of fine aggregates such as crushed fine aggregates, sea sand and blast furnace slag in it and concrete having mixture of two kinds of those fine aggregates in it in order to find out how to deal with the lack of some aggregates. The findings are as follows. In terms of slump, the concrete containing sea sand and blast furnace slag has very low slump values while the concrete having the mixture of crushed fine aggregate and the other fine aggregates showed better workability. In terms of compressive strength, the concrete containing the mixture of two kinds of aggregates showed higher compressive strength. Accordingly, it is likely that the concrete containing the mixture of crushed fine aggregate, sea sand and blast furnace slag is better than the concrete with only one kind of fine aggregates in terms of the usability.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2008년도 춘계 학술발표회 초청강연 및 논문집
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• pp.932-937
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• 2008

The asphalt waste has been collected more than ten thousands' ton from repairing works on the road and excavation repair works, most of them are disposed on land of reclamation. Only a few percentage of wasted asphalt recycled to new one. Therefore, In this study, usage of wasted asphalt and has been done engineered characteristic test for recycling materials of sub-grade and structure. To know the characteristic of asphalt waste, tamping test, bearing-ratio test, permeability test and direct shear test was done using asphalt-sand mixture. The test results shows that, mixed asphalt materials with sand can be used for materials of subgrade-soil and structure.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2000년도 가을 학술발표회논문집(I)
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• pp.395-398
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• 2000

Recently, increasement of usage contents of sea sand in constructing concrete structures due to insufficiency of high quality river sand, led to many studies for steel corrosion and control methods on it in concrete. But, domestic studies for threshold chloride contents of steel corrosion are not so many as those of foreign states. In this study, the electrochemical test as half cell potential measurement and linear polarization method to estimate the corrosion of steel in contents mixed with several levels chloride contents was performed, thereby, pre-mixed chloride were compared with results measured quantitatively for steel corrosion. And, based on these data, a trial to determine threshold chloride contents of steel corrosion was made.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2003년도 가을 학술발표회 논문집
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• pp.15-18
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• 2003

Development of the construction industry generally exhausts natural aggregate. Hence it is problem to the lack of supply and quality deterioration, so the resource saving and protection of environment is made an effort through recycling by-product. This study presents that fundamental properties of concrete which used cooper slag as alternate sand of low fineness modulus and plan of cooper slag as concrete aggregate. Testing factors are concrete's slump, air contents, unit weight and compressive strength. The results of this study are as follows; (1) Concrete slump is generally satisfied with the condition but is inferior to the others in substitution rates 30%. Also air contents are 3.1-4.1% and go up according to increase substitution rate. (2) Unit weight increase in 1.1% as the mixing ratio of cooper slag argument 10%. (3) compressive strength of cooper slag concrete is similar to plain and especially higher 11-15% in W/C 45%, 50%. So it seems that aggregate mixed cooper slag is suitable to low water-cement ratio mixture.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2005년도 춘계 학술발표회 논문집
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• pp.1023-1030
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• 2005

This study is an experiment paper about the ground improvement material which using the waste residual(slag and paper fly ash) by fire. we are research to concern according to the soil to mix the ground improvement material at show strength effectiveness. Also, we can expect a long time strength increase effectiveness as reduce the dryness contraction. They are distinguished to the clay of the reclamation ground and silty sand soil. We examined around an uniaxial compress test and scanning electron microscopy. The uniaxial stress increases according to the increase of the mixed ratio of ground improvement material and the water contents have been reduced the strength value. A clay's improvement effectiveness is big but in the silty sand soil to express small effectiveness. A ground improvement material mixing of the quantity to write can not expect the effect of Ettringite.

• 한국지반공학회논문집
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• 제17권5호
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• pp.129-136
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• 2001

본 논문에서는 석탄회 매립지반의 액상화 가능성을 평가하기 위해 순수 모래시료와 더불어서 모래시료와 석탄회가 혼합된 모래시료에 대한 일련의 진동삼축실험을 변형률제어 방법으로 수행하였다. 실험결과 진동하중에 의해서 시료 내에 발생하는 간극수압의 크기는 작용하는 전단변형률의 크기에 심각하게 영향을 받고, 작용하는 전단변형률이 지반의 한계전단변형률 보다 작은 경우에는 진동수가 높은 조건에서도 간극수압이 발생하지 않음을 알았다. 또한 전단변형률이 약 0.1%보다 작고 한계전단변형률에 가까운 경우에는 순수 모래시료와 비교하여 본 논문에서 조사한 석탄회 함유율 범위 (10%~30%)의 시료에서 간극수압이 더 크게 발생하였다. 반면에, 전단변형률이 큰 경우에는 순수 모래시료에서 간극수압이 크게 발생하는 추세를 보였다. 반복 전단에 따른 간극수압의 발생량은 전반적으로 석탄회 함유율이 증가할수록 커지는 경향을 보였다. 이러한 결과를 근거로 해안이나 하천에 인접한 한계지 개발에 있어서 사질토에 석탄회를 혼합 매립하여 지반을 조성하는 경우에 액상화에 대해서 불안정한 지반이 될 가능성이 있는 것으로 판단되었다.