The Influence Of Property Of The Collapsible Loess On Pile Beating Performance

The soil engineering characteristics and soil layer’s distribution in loess foundation havespecial quality. More and more study on soil-pile interaction of bridge pile in loess area hasbeen paid attention to. In this dissertation,based on the existing theory, by the result of tests insituation,and numerical simulation,the soil-pile interaction of bridge pile in loess area hasbeen analyzed systemically.In this dissertation,based on shear displacement method and elasticity theory, the formulaof estimating the settlement and axial force and the depth of neutral point of pile inself-weight collapsible loess is given. And the spatial axisymmetric finite element model,forthe single pile,is established by the finite difference software (FLAC3D）.Based on themodel,to calculate proper pile length in the self-weight collapsible loess by the superpositionmethod, and it is concluded that,when the distribution of skin friction at the upper and lowerparts of soil is of same pattern, added pile length has no significant influence on distributionof skin friction, but it has on ultimate friction resistance.By this method the influence ofproperty of the self-weight collapsible loess on pile beating performance is analyzed. It isobserved that:(1)when pile is under ultimate capacity the depth of neutral point is related topile length and(2)the influence of collapse coefficient on rest bearing capacity of pile isnonlinear and(3)the quantitative range of the depth of neutral point and the added pile lengthis given.Finally,a close matching between the emulation results with the actual test data assuresthat the model is appropriate for analysis.Under the action of vertical load，the pile and soilshow their leading role in different stages,with the increasing load level.