Effect of Rock Trenching Vibrations on Nearby Structures

Trenching to install deep gravity sewers and drains in medium-to high-strength rock requires large and heavy rock trenchers that produce high levels of vibrations that may affect the structural integrity of nearby utilities and buildings. Although not every vibration causes damage, owners often believe that their structures have been harmed by rock excavation. The resulting disputes can waste a great deal of time and money. In an effort to reduce structural damage and associated disputes, this paper provides guidelines for the safe distance between rock trenchers and nearby buildings and underground structures. Vibration data at different distances from the trencher centerline were collected from five trenching projects in Northwest Ohio. The data analysis suggests a moderate relationship between the vibration level and the distance from the source of vibration. In addition, the risk of damage to nearby structures dissipates significantly and quickly as the distance from the point of excavation increases. Rock trenching should not take place closer than $1.50\mathrm{m}$ for buried structures and $1.00\mathrm{m}$ for residential buildings. Beyond this safe distance, damage to nearby structures should not take place.