Proceedings of the Korean Geotechical Society Conference (한국지반공학회:학술대회논문집)
- 2008.10a
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- Pages.1475-1486
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- 2008
Chemical and Physical Influence Factors on Performance of Bentonite Grouts for Backfilling Ground Heat Exchanger
지중 열교환기용 벤토나이트 그라우트의 시공성에 대한 화학적, 물리적 영향 요소에 관한 연구
- Lee, Chul-Ho (Dept. of Civil, Environmental and Architectural Engineering, Korea University) ;
- Gil, Hu-Jeong (Dept. of Civil, Environmental and Architectural Engineering, Korea University) ;
- Lee, Kang-Ja (Dept. of Civil, Environmental and Architectural Engineering, Korea University) ;
-
Choi, Hang-Seok
(Dept. of Civil, Environmental and Architectural Engineering, Korea University)
;
- Choi, Hyo-Pum (Research&Development Institute, Kunhwa Co., Ltd.)
- 이철호 (고려대학교 건축사회환경공학과) ;
- 길후정 (고려대학교 건축사회환경공학과) ;
- 이강자 (고려대학교 건축사회환경공학과) ;
-
최항석
(고려대학교 건축사회환경공학과)
;
- 최효범 ((주)건화 기술연구소)
- Published : 2008.10.10
Abstract
Bentonite-based grouting has been popularly used to seal a borehole installed for a closed-loop vertical ground heat exchanger in a geothermal heat pump system (GHP) because its high swelling potential. However, if the bentonite-based grouting is conducted in coastal areas, the salinity of groundwater changes in the mineral fabric of bentontie. In order words, an increase of cation concentration in groundwater leads to a reduction in the diffuse double-layer thickness in the bentonite mineral structure, and thus the volume of bentointe-based grouts will decrease proportional to the salinity of groundwater. In this paper, the effect of salinity (i.e., NaCl 0.5M, 0.25M, and 0.1M) on the change of swelling potential for bentonite-based grouts has been quantitatively evaluated for seven bentonite grouts from different product sources. In addition, in case of using addictives such as a silica sand to increase the thermal conductivity of bentonite-based grouts, the possibility of particle segregation has been studied considering the viscosity of grouts and salinity of groundwater.