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Terra Solutions - Technical Corner - Technical Papers - Vibration velocities resulting from the use of explosives in different rock masses.
F. Tavares de Melo. MAXAMPor, S.A., Lisboa Portugal
C. Galiza & A. Vieira. Instituto Superior Engenharia, Porto
INTRODUCTION
The work presents a study of the vibration particle velocity resulting from the use of explosives in different rock masses. This study was performed on three kinds of rock masses, such as granite, limestone and quartzite. There has been a monitoring phase and data collection phase in each situation. Three different laws of propagation of vibration velocity, Johnson (1971), Langefors & Kihlström (1978) and Chapot (1981) were used to calculate their site specific constants by statistical method of multiple linear regressions. After obtaining the constants, studies were made to predict the particle velocities when applying the same explosive charges in the rounds. The vibration values obtained in each round for each kind of rock mass were measured and the two equations compared to register which one had the smaller deviation.
This study shows that the Johnson equation appears to be better at predicting the vibration velocities because it had the smallest deviation acting favourably at a no-damage safety perspective. Using the Langefors equation as a predictor gave good results when applying the safety coefficient of 90 % of the highest particle velocity value obtained in the tests. In conclusion this last predictor can easily be used with good results for preventing vibration damage. The constants were used as a base for the daily work and could be used in future works for the same kind of mass and location. In future projects it would be useful to compare with different laws like Chapot (1971), and create a vibration descriptor map for each location.
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