Research Of Soil Liquefaction And Bearing Performance Of Bucket Foundation Under Seismic Load

In this paper, soil liquefaction and bearing capacity of bucket foundation underseismic load is researched comprehensively. Soil liquefaction, namely shear stress ofsaturated soil under static loading、seepage and dynamic loadings exceeds the shearstrength, and the phenomenon which soil changes from a solid state into liquid occurs.Under impermeable condition(or with the increase of seepage gradient), the volume ofsoil which is suffered with shear force, excess pore water pressure increases, effectivestress of soil decreases to zero, the bearing capacity of soil loses and the deformationof soil increases. Seismic load has a significant effect on soil liquefaction, includingthe peak of seismic acceleration, the duration of earthquake and the seismic intensity.The increasing peak acceleration leads to the decrease of effective stress of soil, theincrease of excess pore pressure, the severity of soil liquefaction and the reduce of thebearing capacity of soil. When the time of the earthquake is longer, the verticaldisplacement and excess pore water pressure of soil changes consistently, which havechanges for small range Initially, are to a certain value as time increases and are onchange lately. In addition, the degree of soil liquefaction has a relationship withdrainage boundary condition of soil, especially the effective stress of soil. The abovephenomenon is obvious with the increase of the soil depth. In drainage condition,when the soil which has close distance from the surface is subjected to seismic load,pore water pressure accumulates continuously and dissipates through soil surface, theeffective stress of soil is large relatively. In contrast, in impermeable condition, porewater pressure ruled out difficultly and roses gradually, the effective stress decreases.Seismic load has a significant impact on the bearing capacity of the soil. By analyzing,the equivalent plastic strain of soil, the displacement corresponding to direction andthe stress have an increasing trend after the seismic loads, the bearing capacity of soildecreases and losses. Finally, the actual project3MW bucket foundation is selectedand is used for validation. Results shows that the changes about soil liquefaction andthe bearing capacity of bucket foundation under the seismic loads are similar with theresults of analysis, namely, in the influence of seismic loads, the deformation andstress of soil increase gradually, plastic deformation occurs early, the stress of soilexceeds the limit shear which leads to the loss of the bearing capacity of soil.