• Geotechnical Engineering
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• v.31 no.2
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• pp.8-18
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• 2015

• 지반과기술
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• v.4 no.2
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• pp.28-36
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• 2007

• Geotechnical Engineering
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• v.36 no.1
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• pp.8-27
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• 2020

• Geotechnical Engineering
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• v.40 no.3
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• pp.74-84
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• 2024

• Geotechnical Engineering
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• v.40 no.4
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• pp.26-35
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• 2024

• Magazine of the Korea Concrete Institute
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• v.14 no.3
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• pp.18-23
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• 2002

구조재료로써 콘크리트의 물리적 특성은 강재와는 달리 시간 의존적이라고 할 수 있다. 즉, 타설 후 재령이 경과함에 따라 압축강도와 탄성계수가 증가함은 물론, 콘크리트 내의 수분이 대기 상태로 증발하면서 부재가 수축하는 건조수축 및 외력의 증감없이 변형률이 증가하는 크리프 특성 등을 가지고 있다. 또한, 콘크리트는 시멘트의 수화반응에 의해 시공초기에 재료의 온도가 급격히 상승하는 발열특성도 동시에 가지고 있다. 이러한 특성들은 구조물의 설계시 무시할 수 없으며, 각 시공단계 및 완성단계의 구조물의 응력에 커다란 영향을 미치게 된다.(중략)

• Magazine of korean Tunnelling and Underground Space Association
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• v.20 no.3
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• pp.54-66
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• 2018

• Magazine of the Korea Concrete Institute
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• v.28 no.6
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• pp.53-56
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• 2016

• Journal of the Korea Institute of Building Construction
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• v.24 no.5
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• pp.529-540
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• 2024

This research aimed to refine the concrete floor finishing for enhancing its performance compared to the traditional way. The new method involved the removing the deteriorated mortar layer and reinforcing the surface to augment the durability and bond strength of the floor surface. This study performed the experience to evaluate the bond strength, drop depth, rebound hammer hardness, and the surface hardness of the surface by adopting traditional and refined method. The results showed the proposed method enhanced the performance on all the metrics. Based on the experiment, the bond strength increased about 2.79 times before installing the finishing material, and the strength also improved about 1.67 times and 1.44 times at the painted finishing and non-painted finishing, respectively. In addition, the drop depth decreased about 4.42 times when adopting the proposed method, which shows the enhanced resistance to declamination compared with applying the traditional way. Lastly, the surface hardness measured by scratch thickness significantly improved about 505% in this experiment. The finding of this study indicates that the proposed method can substantially enhance in bond strendth and durability of floor finishing, reduce the defects of the concrete-based floor, and extend the life of the products.

• Tunnel and Underground Space
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• v.28 no.1
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• pp.1-24
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• 2018

The use of TBM (tunnel boring machine) gradually increases in worldwide tunneling projects. TBM machine are often applied to more difficult and complex geological conditions in urban area, and many problems and difficulties have been reported due to these geological conditions. However, in Korea, there is a lack of research on difficult grounds so far. This paper discussed general aspects of investigation method, and problems of TBM tunneling in difficult grounds. Construction cases that passed through the difficult grounds in worldwide were analyzed and the typical difficult grounds were classified into 11 cases. For each case, the definition and general problems were summarized. Particularly, for mixed ground and boulder ground, and fault zone, which are frequent geological conditions in urban area with shallow depth, classification system, investigation methods and major considerations were discussed, and proposed the direction of future research. This paper is a basic study for the development of TBM construction technology in difficult ground, and it is expected that it will be useful for related research and construction of TBM in difficult ground in the future.