진동 저감을 위한 수직구 발파의 패턴 비교 = Comparision of shaft blasting patterns for vibration reduction

다국어 초록 (Multilingual Abstract)

This study aims, at applying the optimal shaft blasting patterns in the urban area, Vibrations were measured with and without vibration reduction methods at a urban site in Pusan. The results were analyzed with respect to scaled distance, frequency distribution, and blasting pattern.
The conciusions are as follows:
1. The relationship formula between vibration velocity and scaled distance are found with the confidence level of 95%.
without reduction methods : V_(９５)=4041.3350(SD)^(-１.７１７) (square root)
V_(９5)= 2229.0863(SD)^(-１.７１７) (cube root)
with reduction methods : V_(９５)= 563.3637 (SD)^(-１.１９２) (square root)
V_(９５)=436.6020(SD)^(-１.２５３) (cube root)
2. The main frequency of vortical component Is found to the higher than in 100Hz in most of the measurements, while the transverse component has the main frequency lower than 60Hz, in the meanwhile, it is hardly found in the case of longitidual component.
3. Measurements were made at a bulding approximately 5m apart from the blasting site. The blasting pattern with vibration reduction methods shows much lower vibration. The reduction magnitudes are 12.7% for the squre root formula and 13.8% for the cube root when the thres hold limit value in set at 10mm/sec. Comparisions are made with the same charging weight per delay at the same distance.