Abstract:
A study of the vibration propagation mechanism of rigid embedded foundation in layered half-space site was carried out using the indirect boundary element method (IBEM). On the basis of the foundation dynamic stiffness coefficient study, the method applies a concentrated load on the foundation center of mass to obtain the foundation displacement, and combines with the uniform distributed load dynamic Green's function to obtain the vibration response of the surrounding site; the semi-analytical solution is then compared with the finite element and the measured results to validate the accuracy and applicability of the method; and then, taking the impact load and the simple harmonic load as an example, the site vibration response and its decay law under the conditions of the three types of soil layers: the normal sequence, the soft interlayer, and the inverse sequence are discussed. Then, the vibration response of the site and its attenuation law under the conditions of normal sequence, soft interlayer and inverse sequence are discussed as examples. The study shows that the change of soil layer sequence makes the propagation characteristics of the site change significantly. Under the impact load, the peak velocity response and attenuation rate of the normal sequence site are larger, while the attenuation rate along the depth direction of the three sequences is basically the same (the attenuation rate of the peak velocity along the depth direction from 10 m to 55 m is about 92%). Under simple harmonic loading, it is considered that the inverse sequence sites are more likely to attenuate a portion of the energy in the middle and high frequency bands, which makes the vibration response of the inverse sequence sites attenuate faster during the middle and high frequency loading.