Response of pipelines to blast loading

Blasting is often used in construction, quarrying and mining to fracture rock and remove overburden. While blasting is an efficient method for carrying out these tasks, there are often severe restriction on the size of blasts and distance to surrounding structures and infrastructure. In the case of buildings, such as residential and commercial structures, there are national and international standards available that set the maximum levels of allowable ground vibrations due to blasting. For most civil infrastructure, such as pipelines and transmission towers, there are no such standards. The maximum allowable ground vibration levels are normally set by the operators of such facilities and are typically based on historical practice. Due to lack of data and industry standards, these limits vary from one operator to another and are normally extremely conservative. This paper reviews the performance of pipelines during past earthquakes and estimates the possible range for blast induced ground motions that would not cause any damage to pipelines of various materials. Results from a field study on the response of a water pipeline to blast vibrations are also presented with the aim of establishing a rational method for determining the effect of blasting on surface mounted pipelines. A lead-jointed mild-steel cement-lined (MSCL) pipe was subjected to controlled blasts in order to assess the blast induced stresses on the pipe. It has been found from this study the vibration limits, in terms of peak particle velocity, can be increased to more than 10 times the currently imposed level without compromising the integrity of the pipeline.