Transient Response Analysis Of Frame Structure Embedded Partially In Soil By The Method Of Reverberation-Ray Matrix

There are no methods to calculate the transient response of pile foundations under a large amount of exist structures in actual engineering, the most typical one is frame structure embedded partially in soil under impact. In fact, the transient response research of frame structure embedded partially in soil not only has instructive significance, but also is the theoretical basis for designing marine platform, oil-line trestle and open type wharf under impact. Thus, I dedicated myself to the research on the dynamic response of frame structure embedded partially in soil under impact with respect to wave motion.Based on elastic wave motion, the principle of reverberation-ray matrix method of frame structure embedded partially in soil is researched first. Axial and flexural wave motions are presented in soil-pile system. Scattering matrix at joints is obtained from motion's equations and compatibility conditions. The reverberation-ray matrix for the structures is determined in terms of scattering matrix, phase matrix and permutation matrix. Thus, the transient response of the structures is determined from the inverse Fourier transform.The general equations of frame structure embedded partially in soil are reduced, and then transverse wave of pile and elastic beam are obtained. The transient response of no damaged or damaged frame structure is also obtained. The influence of impulse duration, direction, and damage position, extent on the velocity wave at the impulse action point is addressed. It is shown that impulse direction has a great effect on velocity wave.The transverse wave of frame structure embedded partially in soil is obtained. And the results are checked in terms of motion's equations in time domain at joints and wave-front arriving time. The effect of slenderness ratio, impulse duration, soil-pile stiffness ratio, the depth of buried pile and end restraint on axial wave, shear force wave and moment wave is analyzed, which shows that the depth of buried pile and the end restraint have great effect on them. Furthermore, the transient response of frame structure embedded partially in soil is compared with the one of portal frame.Damage identification of frame structure embedded partially in soil is researched. Wave form characteristic of axial and transverse velocity is analyzed if impulse acts axially, laterally or obliquely. And it is found that the damage of frame structure embedded partially in soil can be identified via axial velocity under axial or oblique impulse.Finally, main conclusions are draw and further research and suggestions are proposed.