Blast vibration limits on a sewer tunnel from direct strain measurements

摘要

Comparative measurements of peak particle velocity and strain were made on the internal surface of a 100 year old brick ovoid sewer tunnel which was subject to ground vibration from adjacent construction blasting. The measurements confirmed that the plane wave strain theory can be used to determine the strain induced in underground structures from ground vibration measurements. Testing was carried out to determine the strength of the sewer tunnel brickwork, this strength was compared to stress resulting from blast vibration inputs, and hence permissible levels of blast vibration for the sewer tunnel were determined. Following this investigation, blast vibration limits were adopted which were substantially higher than those which had been initially specified.