3D Numerical Simulation Of Seismic Responses Of Pile Groups On Liquefiable Soils

Pile foundation is one main treatment method for soft foundation. Pile foundations in liquefiable soils are damaged seriously indued by earthquake liquefaction from many earthquake case. Consequently, in order to investigate the mechanism of pile-soil interaction and develop a rational seismic design of pile groups on liquefiable soils, the analysis of seismic responses of pile groups found on liquefiable soils are key problem earging to overcoming for geotechnical engineers.Based on the Flac3D program, the numerical modelling for the analysis of seismic responses of pile-groups on liquefiable soils are described in this dissertation. Two cases of same input seismic wave, and with or without loading were carried out to investigate the seismic responses of pile groups in liquefiable soils. Moreover, the contribution principles of soil acceleration, excess pore water pressure, bending moments of pile are further discussed. And results are reached as shown in the following:(1) The lateral displacement of pile groups decreases with in increase of burried pile depth. The phenomenon of liquefaction trending to downward are observed.(2) The values of displacement and bending moments are influenced by the fixed or free pile top. The value of displacement in the fixed pile top model is larger than that in free pile top model.(3) The bending moments of the piles are on 1/3 part from pile bottom. The bending moments of center piles are less than those of edge piles in both models.(4) The burried depth of soil play role of the generation rate of pore water pressure in the discussed models, but the influence of effect of pile groups is little.The results can provide references for the seismic design of pile-groups foundation found on liquefiable soils. Also some result can be used to direct reinforce and treatments of pile-groups on the liquefiable soils.