발파시 터널 숏크리트의 최대입자속도와 부착상태평가 분석 = Analysis of the peak particle velocity and the bonding state of shotcrete induced by the tunnel blasting

국문 초록 (Abstract)

숏크리트의 부착강도는 천정부의 낙반방지와 발파진동에 의한 숏크리트 탈락방지에 중요한 역할을 하는 요소이다. 따라서, 숏크리트의 부착상태평가는 품질관리의 주요 요소가 될 수 있다. 본 연구는 터널 내 발파에 의하여 숏크리트에 미치는 최대 입자속도를 예측하고, 발파 진동에 의한 숏크리트의 부착상태를 평가하기 위하여 수행되었다. 이를 위하여 현재 시공중인 터널현장에서 피난연락갱의 발파시 본선부 및 서비스 터널의 발파진동을 측정하였으며 충격반향시험을 수행하여 숏크리트-암반의 부착상태를 평가하였다. 충격반향시험 신호분석을 위하여 시간-주파수 영역 해석 기법을 도입하였으며 평가결과, 국내에서 일반적으로 시행되는 발파조건에서는 숏크리트와 암반의 부착력 손실(들뜸 현상)은 거의 발견되지 않았으며, 숏크리트 부착력 손상 가능성은 낮은 것으로 판단되었다.

다국어 초록 (Multilingual Abstract)

Bonding strength of shotcrete is a significant influential factor which plays the role of collapse prevention of tunnel crown and of debonding prevention of shotcrete induced by the blasting vibration. Thus, the evaluation of the shotcrete bonding state is one of the core components for shotcrete quality control. In this study, the peak particle velocities induced by blasting were measured on the shotcrete in a tunnel construction site and its effect on the bonding state of shotcrete is investigated. Drilling and blasting technique was used for the excavation of intersection tunnel connecting the main tunnel with the service tunnel. Blast-induced vibrations were monitored at some points of the main tunnel and the service tunnel. The shotcrete bonding state was evaluated by using impact-echo test coupled with the time-frequency domain analysis which is called short-time Fourier transformation. Analysis results of blast-induced vibrations and the time-frequency domain impact-echo signals showed that the blasting condition applied to the excavation of intersection tunnel hardly affects on the tunnel shotcrete bonding state. The general blasting practice in Korea was evaluated to have a minor negative impact on shotcrete quality.

참고문헌 (Reference)

• 1 송기일, "충격 반향 기법을 이용한 숏크리트 배면 접착 상태 평가에 관한 수치해석적 연구" 사단법인 한국터널지하공간학회 10 (10): 105-118, 2008
• 2 문상조, "지하철 대단면 터널의 설계와 시공관리 사례" 265-292, 1999
• 3 안경철, "숏크리트의 부착강도 측정을 통한 지보설계" 31-45, 2004
• 4 송기일, "비파괴 시험 기법을 이용한 숏크리트 배면 접착상태 평가에 관한 실험적 연구" 사단법인 한국터널지하공간학회 11 (11): 71-83, 2009
• 5 장석부, "대단면 암반터널의 안정성에 미치는 숏크리트 부착강도의 영향에 관한 연구" 사단법인 한국터널지하공간학회 7 (7): 305-311, 2005
• 6 Nakano, K, "Vibration and cracking of tunnel lining due to adjacent blasting" 462 : 53-62, 1993
• 7 McCreath, D.R, "Survivability of shotcrete near blasts in Rock Mechanics" Balkema 277-284, 1994
• 8 Melbye, T, "Sprayed concrete for rock support" MBT International 154-155, 2001
• 9 Davis, AG, "Rapid and economical evaluation of concrete tunnel linings with impulse response and impulse radar non-destructive methods" 38 : 181-186, 2005
• 10 Gibson, A, "Lamb Wave Basis for Impact-Echo Method Analysis" 131 (131): 438-443, 2005
• 11 Ansell, A, "In situ testing of young shotcrete subjected to vibration from blasting" 19 : 587-596, 2004
• 12 Sansalone, M, "Impact-Echo:Nondestructive Evaluation of Concrete and Masonry" Bullbrier Press 338-, 1997
• 13 Xie, X, "Evaluation of grout behind the lining of shield tunnels using ground-penetrating radar in the Shanghai Metro Line, China" 4 : 253-261, 2007
• 14 Kendorski, F.S, "Effect of blasting on shotcrete drift linings" 25 : 38-41, 1973
• 15 Tannant, D.D, "Dynamic testing of shotcreted drifts" GRC, Laurentian University 20-, 1993
• 16 Carino, NJ, "Detection of voids in grouted ducts using the impact-echo method" 89 (89): 296-303, 1992
• 17 Song, K.I, "Bonding state evaluation of tunnel shotcrete applied onto hard rocks using the impact-echo method" 42 : 487-500, 2009
• 18 Wood, D.F, "Blast damage to steel fibrereinforced shotcrete, Fiber Reinforced Concrete-Modern Developments" UBC Press 241-250, 1994
• 19 Cartwright, P, "Application of the acoustic energy meter for assessment of tunnel lining condition" 333-338, 2001
• 20 Ansell, A, "A literature review on the vibration resistance of young and early age concrete" Structural Engineering Royal Institute of Technology 2002