편마암 부지의 발파진동 감쇠특성 분석

Abstract

본 연구에서는 편마암 부지에서 발파공사 시 인접 구간에 위치한 보안물건에 대해 허용기준을 만족하기 위하여 현장 시험발파를 통하여 발파진동 추정식을 산정하고, 국토교통부 설계 발파추정식 및 암종에 따라 분석한 기존의 제안된 발파진동 추정식과 비교 분석하였다. 암종이 편마암인 5개의 지점에서 시험발파를 수행하고 자승근과 삼승근 환산거리를 적용하여 회귀분석하여 발파진동 상수(K)와 감쇠지수(n)를 통하여 각각의 발파진동 추정식을 산정하였다. 산정된 발파진동 추정식은 자승근 환산거리를 적용하면 발파진동 상수 K=167.57, 감쇠지수 n=1.62으로 산정되었으며, 삼승근 환산거리를 적용할 경우에는 발파진동 상수 K=311.91 감쇠지수 n=1.72로 산정되었다. 삼승근식이 좀 더 신뢰성이 높았으며, 국토교통부 추정식과 유사하게 나타났다. 암종별로 비교시에는 화강암, 석회암과 관련된 발파진동 추정식보다 낮게 나타났으며, 이는 다른 편마암 관련 추정식과도 유사한 결과를 나타냈으며, 편마암 관련 추정식과 비교시 중간정도의 유사성을 나타났다. 암종이 동일할지라도 그 분류가 다를 수 있음에 따른 차이가 원인이 될 수도 있고 발파영향에 환경적인 요인도 있을 거라 보이며 좀 더 상세한 분류와 같은 비교 표본을 수집하여 향후 발파진동 추정식을 분석하는 것도 필요하다고 판단된다.| In this study, the equation for blast-induced vibration expectation was calculated through on-site test blasting to satisfy the permissible standards for security object located in the adjacent section during blasting work at the gneiss site. And it was compared and analyzed with the previously proposed equation for blast-induced vibration expectation analyzed according to the blasting estimation formula designed by the Ministry of Land, Infrastructure and Transport and the type of rocks. The test blasting was performed at five sites where the rock quality was gneiss, and the regression analysis was performed by applying the scaled distances of the square root and the cube root. After that, each equation for blast-induced vibration expectation was calculated using the blasting vibration constant(K) and damping index(n).

When the square root conversion distance was applied, the equation for blast-induced vibration expectation was calculated as a blasting vibration constant(K) = 167.57 and a damping index(n) = 1.62. In the case of applying the triple root conversion distance, the blast vibration constant(K) = 311.91 and the damping index(n) = 1.72 were calculated. The equation for blast-induced vibration expectation applying the three-square root equation was a bit more reliable and it appeared similar to the estimation formula of the Ministry of Land, Infrastructure and Transport. When comparing by rock types, it was found to be lower than the equation for blast-induced vibration expectation related to the granite and the limestone. The similar result was also obtained with other gneiss-related estimation formula and when compared with the gneiss-related estimation formula, it showed a moderate similarity. Even if the rock types are the same, the differences in classification criteria may be the cause, and it seems that there are environmental factors in the blasting effect. So it is judged that it is necessary to analyze the equation for blast-induced vibration expectation in the future by collecting comparative samples such as a more detailed classification.