Precutting of Tunnel Perimeter for Reducing Blasting-Induced Vibration and Damaged Zone – Numerical Analysis

다국어 초록 (Multilingual Abstract)

Cost-effective tunnel excavation can be achieved with the blasting method. Unfortunately, blasting technique brings with it blastinginducedvibration and noise, which can cause critical social problems such as public complaints. Thus, the development of a novel tunnelexcavation method, one that can reduce the blasting-induced vibration, is strongly demanded for the effective management of urbanspaces. Thus, this study introduces an innovative vibration-reduced excavation method that combines the conventional blastingtechnique with the precutting process and carries out a feasibility study of the proposed tunnel excavation method using threedimensionalfinite element analyses. The micro-scale study focuses on the stopping holes and contour holes while the macro-scale studydeals with the case of a real scale tunnel. From the micro-scale analyses, it can be deduced that the proposed method is effective for thereduction of blasting-induced vibration compared to the conventional line-drilling method. From the macro-scale simulation, it is foundthat the reduction of blasting-induced vibration is independent of the thickness of the precutting free surface but dependent on the depthof the precutting free surface. As the depth of the precutting free surface increases, blasting-induced vibrations as well as the depth of theexcavation-damaged zone can be significantly reduced. Vibration energy induced by blasting does not transmit through the free surfaceand is trapped inside the target tunnel face. Guided blasting waves cause stress concentration at the target face and maximize the blastingefficiency. It is expected that the construction cost will decrease due to a decrease in the number of drilling holes, the weight of theexplosive charges, the overbreak space, and the excavation-damaged zone. In particular, the reductions of the overbreak space andexcavation-damaged zone enhance the safety of tunnel construction.

참고문헌 (Reference)

1 조계춘, "절리암반의 변형률 의존적 전단탄성계수 및 감쇠비 특성을 고려한 터널의 내진 해석" 사단법인 한국터널지하공간학회 12 (12): 295-306, 2010

2 오태민, "연마재 워터젯 변수가 암석제거에 미치는 영향" 사단법인 한국터널지하공간학회 14 (14): 421-435, 2012

3 이인모, "굴착선 주변공 발파의 암반손상을 고려한 터널 안정성 검토" 한국지반공학회 19 (19): 167-178, 2003

4 Lisitsyn, I. V., "Use of inductive energy storage for electric pulse destruction of solid materials" 6 (6): 105-108, 1999

5 International conference of building officials, "Uniform building code"

6 Dudoladov, L. S., "Thermal rock breaking" 5 (5): 194-198, 2006

7 Momber, A. W., "Test parameter analysis in abrasive water jet cutting of rocklike materials" 34 (34): 17-25, 1997

8 Holmberg, R., "Swedish approach to contour blasting" 113-127, 1979

9 Zhongzhe, J., "Splitting mechanism of rock and concrete under expansive pressure" 141-148, 1988

10 Lysmer, J., "Shear waves in plane infinite structures" 98 (98): 85-105, 1972

11 Konya, C. J., "Rock blasting and overbreak control, FHWA-HI-92-001"

12 Song, K. I., "Numerical simulation of the impactecho method for the bonding state evaluation of tunnel shotcrete" 47 (47): 1274-1288, 2010

13 Howie, J. A., "Numerical simulation of seismic cone signals" 42 (42): 574-586, 2005

14 Jeng, F. S., "New development of waterjet technology for tunnel excavation purposes" 19 : 438-439, 2004

15 Dey, K., "Investigation of blast-induced rock damage and development of predictive models in horizontal drivages" ISM 2004

16 MIDAS-GTS, "Geotechnical & tunnel analysis system"

17 Chollette, D., "Fracture stresses induced by rock splitters" 13 (13): 281-287, 1976

18 Res, J., "Environment-friendly techniques of rock breaking" A.A. Balkema 2003

19 Uysal, O., "Effect of barrier holes on blast induced vibration" 45 (45): 712-719, 2008

20 Parsakhoo, A., "Demolition agent selection for rock breaking in mountain region of hyrcanian forests" 3 (3): 384-391, 2009

21 Rustan, L. N., "Controlled blasting in hard intense jointed rock in tunnels" 78 (78): 63-68, 1985

22 Starfield, A. M., "Compression waves generated in rock by cylindrical explosive charges, A comparison between a computer model and field measurement" 5 (5): 65-77, 1968

23 Shao, P., "Applying high voltage pulse discharge in rock blasting: Theoretical problems" 5 : 349-353, 2010

24 Histake, M., "Analytical contribution to tunnel behavior caused by blasting" E191-E194, 1983

25 Park, D., "A numerical study on the screening of blast-induced waves for reducing ground vibration" 42 (42): 449-473, 2009