Assessment of the Swedish Standard for blasting induced vibrations
Examensarbete för masterexamen
Structural engineering and building technology (MPSEB), MSc
Since 1989 the Swedish Standard for blasting induced vibrations has been based primarily on distance and overburden. However, there is an uncertainty about the fundamentals which the Standard is based on, making room for optimization. The thesis aims to evaluate the Swedish Standard for blasting induced vibrations, by studying velocity- and frequency response of the governing parameters of wave propagation. A parametric study with numerical models was conducted using finite element method. The parametric study was divided into material and geometrical properties such as degree of saturation, Poisson’s ratio, Young’s modulus, depth of overburden layer, distance from blast ,and angle of incidence. A poroelastic material model was created by coupling the elastic properties of the solid material with the water stored within the porous structure. The poroelastic material model resulted in velocity- and frequency responses which were comparable with the guidance levels of the Swedish Standard. In conclusion, distance and overburden are applicable parameters. However, the blasting induced vibration is sensitive to changes in degree of saturation, Poisson’s ratio, depth of the overburden surface layer, and to the angle of incidence. As the distance between the blast and the measurement point increases, the frequency range in the vibration was lowered and the risk for damage increases, as buildings are more susceptible to damage at lower frequencies. The P-wave is dominant if the blast is located below the building, however, if the angle of incidence changes, the Rayleigh wave becomes dominant. The frequency response of the Rayleigh wave is lower than for P-waves, thus guidance levels may be set differently depending on which is the dominant wave. A frequency based analysis generates the possibility to combine distance, overburden, material-, geometrical- and possible unidentified parameters, thus simplifying the method of establishing guidance levels for blasting induced vibrations in the soil structure.
Building Futures , Samhällsbyggnadsteknik , Teknisk mekanik , Building Futures , Civil Engineering , Applied Mechanics