• Geomechanics and Engineering
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• 제16권4호
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• pp.375-384
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• 2018

Unconfined compressive strength (UCS) of high plasticity clayey soil mixed with 5 and 10 % of Portland cement and four chemical agents such as sodium hexametaphosphate, aluminum sulfate, sodium carbonate, and sodium silicate with 0, 5, 10, and 20% concentrations was comparatively evaluated. The individual and combined effects of the cement and chemical agents on the UCS of the soil mixture were investigated. The strength of the soil-cement mixture generally increases with increasing the cement content. However, if the chemical agent is added to the mixture, the strength of the cement-chemical agent-soil mixture tends to vary depending on the type and the amount of the chemical agent. At low concentrations of 5% of aluminum sulfate and 5% and 10% of sodium carbonate, the average UCS of the cement-chemical agent-soil mixture slightly increased compared to pure clay due to increasing the flocculation of the clay in the mixture. However, at high concentrations (20%) of all chemical agents, the UCS significantly decreased compared to the pure clay and clay-cement mixtures. In the case of high cement content, the rate of UCS reduction is the highest among all cement-chemical agent-soil mixtures, which is more than three times higher in comparison to the soil-chemical agent mixtures without cement. Therefore, in the mixture with high cement (> 10%), the reduction of the USC is very sensitive when the chemical agent is added.

• 한국지반환경공학회 논문집
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• 제14권2호
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• pp.51-55
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• 2013

연약지반을 개량하기 위한 심층혼합처리공법과 같은 다양한 공법은 지반보강을 위하여 그라우트를 광범위하게 사용하고 있다. 반복하중 및 동하중을 받는 지반-구조물계의 설계에 사용되는 중요한 동적변수는 사질토 및 화강풍화토, 암시편에 관하여 많이 연구 발표되었다. 하지만 그라우트로 보강된 지반에 대한 내진설계 연구는 미비한 실정이다. 이에 본 연구에서는 공진주시험기를 이용하여 점성토와 보통 포틀랜드 시멘트의 함수비와 그라우트 주입률의 변화에 따른 전단변형률과 전단탄성계수의 상관관계를 Ramberg-Osgood Model로 정규화하여 비교 분석하였다. 그 결과 동적계수는 함수비와 그라우트 주입율에 의해 영향을 받는 것으로 나타났다.