BLASTING PLANS/BLAST AND VIBRATION MONITORING


Blasting is employed where large quantities of hard material must be removed and other methods such as ripping will not be effective. Typical situations include highway cuts, site developments where rock must be removed to achieve a level area for construction, major dam construction and mining. To conduct blasting operations, a blasting plan is frequently required in order to obtain essential permits. Preparation of a blasting plan may require extensive characterization of rock conditions, rock mechanics analyses of planned cuts, and attenuation analysis of the effects of blasting on nearby structures. A blasting plan will typically specify a maximum particle velocity at sensitive locations and will provide an attenuation relationship to be used for determining charge size.

Blasting plans will normally provide for monitoring of peak particle velocities at critical structures or at the closest occupied residences. A seismograph that records motion on three orthogonal axes is typically used to monitor blasting vibrations. These instruments have evolved into small battery-operated units that are triggered by the initial motion to record the motions associated with blasting. The data can be downloaded into a laptop computer for evaluation.


Instrumentation used to monitor vibrations due to blasting and other sources such as construction activities.




Project profiles for D'Appolonia projects involving structural vibration monitoring, blasting plan preparation and blast monitoring are provided in the following:


EXAMPLE PROJECTS


Monitoring of Building Vibrations During Nearby Construction Activities

D'Appolonia was retained to perform pre- and post-construction surveys and vibration monitoring during pile driving operations for installation of steel sheeting along a section of the south shore of the Allegheny River at an apartment complex in the Strip District of Pittsburgh, Pennsylvania.


VE Study and Design Services for Kentucky Lock Addition Project

D’Appolonia had the lead for geotechnical aspects of construction of a cofferdam in an area characterized by unusually hard and abrasive limestone that had a highly irregular surface. Our responsibilities included evaluation of in-the-wet rock excavation techniques, development of an underwater blasting plan, and monitoring of the effects of blasting on existing structures and aquatic life.


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