Such impacts are generally the result of errant ground vibrations and air overpressure waves generated by the detonation process. If left unchecked, such disturbances can lead to complaints, damages and other avoidable events. This is especially true when projects are in close proximity to or carried out in urban settings.
This blog article will present the best practices required to successfully carry out blasting operations in sensitive environments.
Steps for establishing blasting criteria and readiness in sensitive areas
Implementing blasting practices in proximity to sensitive environments is a multi-step process requiring stringent planning and analytical and monitoring components. An overview of the primary steps applied by BBA’s drilling and blasting experts is presented in detail below:
Prior to blasting
- Map all critical surface and underground infrastructures and equipment or components within these infrastructures that may have an increased sensitivity to vibrations.
- Plan and execute pre-blasting visual surveys or inspections of all critical infrastructures in proximity to the blasting activity. This makes it possible to identify possible structural flaws or weaknesses that could be aggravated under blasting-induced dynamic loading conditions.
- Consult local regulatory standards for vibration and air-overpressure thresholds, which often differ depending on the type of infrastructure or residing equipment.
- Establish a clear, concise and informative communication plan with stakeholders who may be impacted by the sensory disturbances often associated with blasting events. Such a plan often has the effect of fostering the project’s social acceptability.
- Develop an instrumentation and monitoring plan consisting of both fixed and mobile monitoring devices, including seismographs for vibration and air overpressure monitoring, static or dynamic extensometers and crack meters, and temperature gauges.
- Design a blasting plan based on critical distances and established vibration limits. At this stage, the maximum allowable charge per delay is typically determined based on the distance of sensitive receptors to the projected blasting activities and standard site attenuation constants for vibrations and air overpressure.
Including BBA’s team of experts to support the pre-blast process provides significant added value to the front-end planning phases of the project by minimizing delays often linked to permitting, technical challenges and overall social acceptance criteria often encountered when blasting in urban environments. The BBA team works actively with its clients to establish conventional and non-conventional blasting methods that are adapted, optimized and comply with existing regulations.