Nonlinear Analysis Of Pile-Soil Interaction In Lateral Spreading Of Liquefied Ground

During strong earthquake, liquefied ground under gravity frequently has horizontallyspreading deformation which is usually large and permanent. As a main type of seismicdamage, it causes serious damages of highways, railways, bridges, docks, embankments,buildings, underground structures and lifeline engineerings in liquefied area. However, thedamage of piles induced by lateral spreading of liquefied ground is more serious. Therefore,the influence of ground flow on pile-soil interaction and piles' internal force and deformation,is always the hot spots in geotechnical engineering. Based on Biot's dynamic consolidationtheory for two-phase mixture, the seismic response analysis for the pile-soil interaction in thelateral spreading and liquefied slope, is simulated by a FE-FD coupled method. In numericalanalysis, u-p formation of dynamic consolidation equation and cyclic elasto-plasticconstitutive model are used. Using updated Lagrangian method, large deformation ofliquefied ground is considered. Simulating the process of shaking test, mechanism of pile-soilinteraction in liquefied and laterally spreading slope is studied. Main work is as follow:(1) Using simplified two-dimensional model of single pile, the interaction betweensingle-row piles and Soil is simulated. By calculating the situations under different inclination,the effects of liquefied and laterally spreading ground on internal force and deformation areobtained. The effects of inclination on piles' internal force and displacement are discussed.(2) The two-dimensional model of free soil under the same loading is also analyzed.The deformations of pile and free soil are compared in order to get the relative displacementof pile to free soil. The effects of the relative displacement on distribution of piles' internalforce are studied.(3) Using simplified two-dimensional model of double pile, the interaction betweendouble-row piles and soil is simulated. The effects of liquefied and laterally spreading groundon piles' internal force and deformation are discussed. The difference of internal force anddeformation between front pile and behind pile is analyzed. Comparing the results, it isobtained how the internal force and displacement of piles varies with inclination.