Attenuation of Ground Vibration on Saturated Silt Clay and Rock Bases

By actual measuring and theory analysis, this paper obtains the saturated water mass density and shear modulus of saturated soil , and also the major factor affecting near source attenuation by the mteration of soil skeleton and water , the later also being the major factor affecting far source attenuation. The paper inquiries into the affect of the depth of underground water on the wave propagation. For rock base, as the wave velocity of rock body wave is high and the body wave attenuation much faster than the surface wave does, so the near source attenuated generally faster than the soil surface does. The elastic property of rock is better than the soil, although its self-excited vibration frequency is high; the damping of the material is small. So the far source attenuated much slower than soil does. The paper also inquiries into the effect of the covering layer of rock surface, the tread of rock structure, and the ditch on the attenuation of vibration wave. The geometry attenuation factor and soil attenuation factor in the formula of attenuation calculation are also recommended in the paper