• 한국해양공학회지
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• 제26권3호
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• pp.39-45
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• 2012

This paper investigates the strength characteristics and stress-strain behaviors of waste fishing net (WFN)-added lightweight soil. The lightweight soil, which consisted of dredged soil, crumb rubber, and cement, was reinforced with WFN in order to increase its shear strength. Glue treated WFN was also added to lightweight soil to improve the interlocking between the soil mixture and WFN. Three kinds of test specimens were prepared: unreinforced lightweight soil, reinforced lightweight soil without glue treatment, and reinforced lightweight soil with glue treatment. Several series of laboratory tests were carried out, including flow value tests, unconfined compression tests, and SEM analyses. From the experimental results, it was found that the peak strength of the reinforced lightweight soil with glue treatment was increased by the increased interlocking between the soil mixture and WFN, which was induced from the bonding effect. The stress-strain relation of the reinforced lightweight soil, irrespective of the glue treatment, showed a more ductile behavior than that of the unreinforced lightweight soil.

• 한국해양공학회지
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• 제19권6호통권67호
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• pp.44-49
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• 2005

This paper investigates strength characteristics and stress-strain behaviors of unreinforced and reinforced lightweight soils. Lightweight soil, composed of dredged soil, cement, and air-foam, was reinforced by a waste fishing net, in order to increase its compressive strength. Test specimens were fabricated by various mixing conditions, such as cement content, initial water content, air content, and waste fishing net; then, unconfined compression tests were carried out on these specimens. From the test results, it was shown that reinforced lightweight soil had different behavior after failure, even though it had similar behavior as unreinforced lightweight soil before failure. The test results also showed that stress became constant after peak strength in reinforced lightweight soil, while the stress decreased continuously in unreinforced lightweight soil. It was observed that the strength was increased due to reinforcing effect by the waste fishing net for most cases, except high water content greater than $218\%$. In the case of high water content, a reinforcing effect is negligible, due to slip between waste fishing net and soil particles. In reinforced lightweight soil, secant modulus (E50) was increased, due to the inclusion of waste fishing net.

• 한국해양공학회지
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• 제22권4호
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• pp.51-58
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• 2008

The objective of this study was to investigate the mechanical characteristics of fiber-reinforced lightweight soil using waste fishing net or monofilament for recycling both dredged soils and bottom ash. Reinforced lightweight soil consists of dredged soil, cement, air foam, and bottom ash. Waste fishing net or monoiament was added the mixture in order to increase the shear strength of the lightweight soil. Test specimens were fabricated with various mixing conditions, including waste fishing net content and monofilament content. Several series of unconfined compression tests and direct shear tests were carried out. From the experimental results, it was found that the unconfined compressive strength, as well as the stress-strain behavior of reinforced lightweight soil was strongly influenced by mixing conditions. In this study, the maximum increase in shear strength was obtained with either a 0.5% content of monofilament or 0.25% waste fishing net. The unconfined compressive strength of reinforced lightweight soil with monofilament was greater than that of reinforced lightweight soil with waste fishing net.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2006년도 춘계 학술발표회 논문집
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• pp.383-393
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• 2006

This paper investigates strength characteristics and stress-strain behaviors of geogrid mixing reinforced lightweight soil. The lightweight soil was reinforced with geogrid in order to increase its compressive strength. Test specimens were fabricated by various mixing conditions including cement content, initial water content, air content and geogrid layer and then unconfined compression tests were carried out. From the experimental results, it was found that unconfined compressive strength as well as stress-strain behavior of lightweight soil were strongly influenced by mixing conditions. The more cement content that is added to the mixture, the greater its unconfined compressive strength. However, the more initial water content or the more air foam content, the less its unconfined compressive strength. It was observed that the strength of geogrid reinforced lightweight soil was increased due to reinforcing effect by the geogrid for most cases except cement content less than 20%. In reinforced lightweight soil, secant modulus $(E_{50})$ was increased as the strength increased due to the inclusion of geogrid.

• 한국지반공학회논문집
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• 제22권7호
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• pp.37-44
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• 2006

본 연구는 지오그리드 혼합 보강경량토의 응력-변형 거동과 강도 특성에 대해 조사하였다. 경량혼합토의 압축강도를 증진하기 위해 경량혼합토에 지오그리드를 혼합하였다. 시험 공시체는 다양한 종류의 배합조건 즉, 시멘트 함유율, 함수비, 기포 함유율에 따라서 각각 제작되어졌고, 여러번의 일축압축강도시험이 수행되었다. 시험결과로부터, 경량혼합토의 일축압축강도와 응력-변형 거동은 배합조건에 의해 큰 영향을 받는 것으로 나타났다. 시멘트 함유율이 증가됨에 따라 일축압축강도 또한 증가한다. 그러나 초기 함수비나 기포 함유율이 증가함에 따라 일축압축강도는 감소하였다. 거의 모든 경우에서 지오그리드에 의한 보강 효과 때문에 지오그리드 보강경량토의 강도가 증가되는 것이 관찰되었다. 지오그리드 혼합 보강경량토의 응력-변형률 관계는 취성거동이라기 보다는 연성적인 거동특성을 가졌다. 보강경량토에서 할선 탄성계수 ($E_{50}$)는 지오그리드 함유로 인해 강도가 증가함에 따라 증가되었다.

• 한국지반공학회논문집
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• 제24권1호
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• pp.101-110
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• 2008

본 연구에서는 준설토 재활용을 위한 단섬유 보강 Bottom ash 혼합경량토의 역학적 특성을 고찰하였다. Bottom ash 혼합경량토는 경량토로서 자체 전단강도증가를 위하여 단섬유를 혼합하였다. 공시체는 단섬유의 함유량, 길이, 직경을 각각 변화시컥 다양한 배합비로 제작하였으며 역학적 거동 특성을 조사하기 위하여 일축압축시험과 직접전단시험이 수행되어졌다. 실험결과 응력-변형 관계는 단섬유의 함유량, 길이, 직경과 같은 배합조건에 크게 의존하는 것으로 나타났고, 단섬유 혼합에 의해 압축강도 및 전단강도가 일반적으로 증가되었음을 알 수 있었다. 단섬유 함유율 0.5%와 길이 4cm에서 최대압축강도가 나타났으며 이러한 결과는 직접전단시험에서도 비슷하게 나타났다. 직경에 따른 압축강도는 단섬유 직경 0.5mm보다 0.25mm에서 더 큰 보강효과가 나타났다.

• 한국지반공학회논문집
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• 제22권11호
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• pp.25-35
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• 2006

본 연구에서는 폐어망을 이용한 보강 경량토의 역학적 특성을 고찰하였다. 본 실험에서 사용된 보강 경량토는 부산 신항 건설현장에서 채취한 준설토와 시멘트, 기포 및 폐어망으로 구성되어졌다. 다양한 함유율의 폐어망이 혼합된 보강 경량토의 보강효과를 고찰하고, 무보강 경량토와 보강 경량토의 거동 특성을 비교하기 위하여 다양한 실내실험이 수행되어졌다. 보강 경량토에 대한 실험결과 응력-변형 관계와 일축압축강도는 폐어망에 의해 큰 영향을 받는다는 것이 나타났다. 보강 경량토의 압축강도는 양생기간이 증가할수록 증가하며, 폐어망을 첨가함으로써 일반적으로 증가하지만, 압축강도 증가량은 폐어망 함유율에 비례하지는 않는다. 본 실험의 경우 폐어망 함유율이 0.25%일 때 최대 압축강도가 발현되는 것을 알 수 있었다. 한편, 보강 경량토의 함수비 변화는 양생기간 7일까지 급격하게 감소한 후 일정한 값에 수렴하였다.

• 한국지반환경공학회 논문집
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• 제13권8호
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• pp.75-84
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• 2012

본 연구에서는 보강재료(폐어망, 본딩처리된 폐어망, 지오그리드)와 보강층수(1층 및 2층)에 따른 정수슬러지 혼합 경량토의 강도 및 용출 특성을 비구속압축시험과 용출시험을 통해 분석하였다. 정수슬러지가 혼합된 경량토는 정수슬러지, 시멘트, 저회를 유동성에 맞춰서 배합 제작되었다. 시험에 사용된 보강재료는 폐어망과 지오그리드이다. 흙입자와 폐어망 사이의 억물림을 증가시키기 위하여 본딩처리를 한 폐어망을 추가로 사용하였다. 정수슬러지가 혼합된 경량토에 대한 강도시험 결과 보강재료에 따른 강도증진은 폐어망, 본딩처리된 폐어망, 지오그리드 순으로 증가하였다. 또한 보강층수가 1층에서 2층으로 증가할수록 강도 역시 증가되는 경향을 나타내었다. 또한 정수슬러지를 혼합한 경량토에 대한 용출시험을 분석한 결과 환경부가 고시한 기준을 만족하는 것으로 나타났다.

• Geomechanics and Engineering
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• 제6권3호
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• pp.249-262
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• 2014

Tire chips and tire chips-soil mixtures can be used as alternative fill material in many civil engineering applications. In this study, the potential benefits of using tire chips as lightweight material to improve the bearing capacity and the settlement behavior of sand slope was investigated experimentally. For this aim, a series of direct shear and model loading tests were conducted. In direct shear tests, the effect of contents of the tire chips on the shear strength parameters of sand was investigated. Different mixing ratios of 0, 5, 10, 15 and 20% by volume were used and the optimum mixing ratio was obtained. Then, laboratory model tests were performed on a model strip footing on sand slope reinforced with randomly distributed tire chips. The loading tests were carried out on sand slope with relative density of 65% and the slope angle of $30^{\circ}C$. In the loading tests the percentage of tire chips to sand was taken as same as in direct shear tests. The results indicated that at the same loading level the settlement of strip footing on sand-tire chips mixture was about 30% less than in the case of pure sand. Addition of tire chips to sand increases BCR (bearing capacity ratio) from 1.17 to 1.88 with respect to tire chips content. The maximum BCR is attained at tire chips content of 10%.