1. Ground Vibration Prediction and Assessment R.M. Thornely-Taylor Rupert Taylor Ltd

2. Noise: SOURCE  PATH  RECEIVER Vibration: SOURCE  PATH  RECEIVER

3. Source term - dependent on excitation, source impedance, mounting impedance, foundation impedance and surrounding lithology Transmission characteristics - dependent on geometry of source, geological characteristics (Lamé constants, loss factor, layering, water tables) Building response - consisting of coupling between foundations and the ground and the dynamic response of the building, and, in the case of re-radiated groundborne noise, the receiving room characteristics Receiver and support impedance. Receiver attitude.

5. Driving-point impedance (z-axis) of seated human body

6. Receiver Issues Foundation coupling transfer functions piled foundations Structure response Power transmission through/up building transmission line floor impedances –vary with location Receiver impedance axes support –standing –chair –bed

7. Propagation Issues Soil parameters on-site measurement bore-hole tests impedance of spherical source in an elastic medium –departs from inverse-square law for velocity pressure and strain dependence of dynamic moduli Uncertainties –unknown features in lithology perched water tables boulders/limestone layers

9. Seismic measurement of P-wave and S-wave velocities

10. Propagation Issues Many wave types body waves (dilatational) shear waves Rayleigh waves Stoneley waves Lamb waves two-phase propagation –liquid in a porous medium –Wave conversion at interfaces SV  P one layer may attenuate several layers may increase propagation at eigenfrequencies progressive change in soil may bend propagation path

11. Correct Source Data Source power –dependent on –source impedance –source mounting/support »resilient elements »dynamic stiffness - frequency dependence »loss factor - frequency dependence Source signal

12. Modelling Empirical –Extrapolating measurements from similar case –Statistical treatment of large numbers of measurements from many cases empirical methods of correcting for changes in parameters Algebraic –Isolator transmissibility –Simple distance function Numerical –Finite element (FEM) –Finite difference (FDM) –Boundary Element (BEM) –Hybrid (FEM/BEM)