지하연속벽 수직구 굴착 시 이격 및 선굴착 발파의 진동 저감 특성 분석

초록

Blasting is often unavoidable at the bottom of deep vertical shafts supported by slurry walls, where the short separation distance between the blast face and the wall can transmit strong vibration to the wall. This study evaluates vibration transmitted to slurry walls during vertical-shaft excavation using 3D numerical analysis, focusing on the influence of sectional blasting configurations and rock mass conditions. A 3D shaft–wall model was developed using field-informed design conditions, and material properties were varied to represent weathered rock, soft rock, and hard rock. Four scenarios—Conventional Blasting, Standoff Blasting, Pre-split Blasting, and Standoff + Pre-split Blasting—were analyzed under identical modeling assumptions to enable consistent relative comparisons across rock types. Wall response was quantified using peak particle velocity (PPV) and its variation with excavation depth. The results indicate that PPV levels and depth-dependent response patterns are sensitive to both blasting configuration and rock condition. Compared with Conventional Blasting, introducing separation and/or a pre-split free surface tends to reduce vibration transmitted to the wall, with the reduction magnitude depending on the rock condition. These findings support comparative selection of vibration-mitigating blasting configurations and help interpret wall vibration trends during deep-shaft construction.

키워드