KSCE Journal of Civil and Environmental Engineering Research (대한토목학회논문집)

Korean Society of Civil Engeneers (대한토목학회)
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Geotechnical Characteristics of DCM-Improved Specimen Under Artesian Pressure

피압 작용에 따른 DCM 개량체의 지반공학적 특성

  • 윤대호 (부경대학교 스마트인프라기술연구소) ;
  • 김윤태 (부경대학교 해양공학과)
  • Received : 2021.09.07
  • Accepted : 2022.02.11
  • Published : 2022.04.01
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Abstract

This study investigated the effect of artesian pressure on mechanical properties of deep cement mixing (DCM)-improved specimens. Various laboratory tests such as unconfined compression test and scanning electron microscope (SEM) were conducted on DCM specimens which curied in a water tank with different artesian pressures. The artesian pressure was determined in consideration of the laboratory scale and the hydraulic gradient in field conditions. Results of experimental tests indicated that unconfined compressive strength, secant modulus, and unit weight of specimen decreased and water content tended to increase as an artesian pressure increased. The stress-strain behavior changed brittle to ductile behaviors as an artesian pressure increased. The outflow water from the water tank reacted with the phenolphthalein solution due to the leaching phenomenon of the improved specimen. SEM analysis also confirmed that a small amount of ettringite was formed between soil particles in the specimens with artesian pressure.

본 연구에서는 피압이 DCM 개량체의 역학적 특성에 미치는 영향을 알아보기 위해 피압의 크기를 조절할 수 있는 공시체용 수조를 제작하여 실내실험을 수행하였다. 피압의 크기는 실험실 규모 및 동수경사를 고려하여 결정하였다. 실험 결과, 피압의 크기가 증가함에 따라 일축압축강도, 할선탄성계수, 단위중량은 선형적으로 감소하고, 함수비는 증가하였다. 또한, 개량체의 응력-변형 거동은 피압이 증가함에 따라 취성에서 연성 형태의 거동을 보었다. 피압 작용으로 발생한 유출수는 개량체의 용탈현상으로 인해 페놀프탈레인 용액에 반응하는 결과를 보였다. 또한, SEM 촬영 결과 입자 사이에 작은 양의 에트린자이트가 형성되어 있는 것을 확인하였다.

Keywords

Acknowledgement

이 논문은 부경대학교 자율창의학술연구비(2021년)에 의하여 연구되었습니다.

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