Standardization of Blast Vibration Damage Threshold for the Safety of Residential Structures in Mining Area

摘要

The paper deals with the study conducted to evaluate the effect of blast produced ground vibration due to openpit blasting on damage potential to the residential structures and subsequently to determine the safe levels of ground vibration for the safety of residential structures and other buildings in mining areas. Under this study, three types of test structures were constructed at two experimental sites in India. The impacts of 341 blasts conducted at the aforesaid mines were monitored at the structures and 1871 blast vibrations data were recorded on or near the structures. The blasting sites were as close as 10 m from the structures to as far as 1800 m. The incoming vibrations had frequency in the range of natural frequency of the structures, thereby causing resonance in the structures and hence amplification of vibration within the structure. The cosmetic cracks in the brick-mud house were detected at peak particle velocities between 51.6 and 56.3 mm/s. The RCC structure of ground floor experienced cosmetic cracks at PPV level of 68.6 to 71.3 mm/s, whereas the cosmetic cracks at first floor were detected at PPV levels of 71.2 to 72.2 mm/s. The minor damage in the mud house was detected at PPV levels of 55.0 to 56.1 mm/s, whereas in brick-mud house it was recorded at PPV levels of 81.0 to 89.7 mm/s. The RCC structure at ground and first floor experienced minor damage at PPV levels of 104 mm/s and 98.3～118 mm/s respectively. The major damage was recorded in mud house at PPV levels of 87.1 to 104 mm/s. The brick-mud house experienced major damage at PPV level of 99.6 to 113.0 mm/s. Major damage was recorded in RCC structure at the ground floor at PPV of 122 mm/s, whereas the first floor experienced major damage at PPV level of 128.9～161 mm/s.