Open Cut » Drilling & Blasting
The structure response of brick veneer test houses in the Muswellbrook and Singleton areas to blasting has been measured and the strength of their structural elements have been determined.
Analysis has shown that the stresses due to blast vibration that are within currently enforced environmental limits are well below damage levels.
The vibration levels at which observable damage to houses occurred from blasting compares to the level determined from structural response and strength of materials considerations.
The structural response effect of 'natural factors', such as ground movement and rainfall, has been determined and compared to the strength of materials and found to be significant in the formation and propagation of cracks in buildings.
The type of structural defects observed in the test houses have been observed in reference houses not exposed to blast vibration or mine subsidence.
The results of this investigation regarding blast vibration levels, structure response and observed damage is consistent with authoritative overseas studies.
A rational and conservative method has been developed for estimating the dynamic vibration induced strains in houses and comparing these strains with cracking strains of building materials and strains resulting from 'natural events' to enable a cause weighting to be determined (if appropriate) without the need of a full structural response investigation.