Study On Laterally Bearing Characteristic Of DX Pile With Theory Analysis And Numerical Analysis

DX pile is a new kind of pile with varied cross-section recently developed. Engineering practice shows that the DX pile has several remarkable advantages, such as high bearing capacity, small settlement. Formerly, a lot of research have been maken about the vertical bearing mechanism and settlement characteristic of DX pile, but the laterally bearing characteristic is almost not involved. This article do a comprehensive research on the laterally bearing characteristic of DX pile via theoretical analysis and numerical analysis. On the base of existing m theory, this article propose a new method which is used to calculate DX pile. This article analyse the factor which can change the laterally bearing characteristic of DX pile, such as geometic parameters of pile and soil parameters, via numerical analysis. At last this article do some work on laterally bearing characteristic of DX pile group by numerical analysis.The following conclusions can be made in this research:1) On the condition that the load, pile length and diameter is the same, DX pile usully has a smaller horizontal displacement which appear on the top of pile than straight pile.2) The bearing bell of DX pile has a function of reducing the horizontal displacement but it has a close relationship to the depth of bearing bell.the depth is smaller,the function is more significant.Usually, when the depth of bearing bell exceed5m, the bearing bell has no longer this function.3) The diameter of DX pile has a significant influence on the laterally bearing characteristic, the more the diameter is, the smaller the horizontal displacement is.4) When the depth of bearing bell is small, variation of the ratio of bell diameter to pile diameter has significant influence on the laterally bearing characteristic of DX pile. The bigger the depth of bell is, the smaller the influence is.5) wo can increase the ultimate bearing capacity of DX pile by adding to bearing bell, when the number of bearing bell change from1to2, the laterally ultimate bearing capacity incrase greatly, when the number of bell change from2to3,4or5, the laterally ultimate bearing capacity do almost not change.6) When DX pile has two bearing bells, if the upper bell is fixed, the more the spacing of bell is, the smaller the ultimate bearing capacity is. 7) The parameters of soil, such as modulus,cohesion and friction angle,have significant influence on laterally bearing characteristic of DX pile, the more these parameters are, the bigger the bearing capacity is. But the variation of these parameters can not change the ultimate depth of bearing bell greatly, when the depth of bearing bell exceed the ultimate depth, it can not reduce horizontal displacement.8) DX pile group which has the same number of pile as straight pile group has bigger laterally ultimate bearing capacity, the bigger the spacing of pile in the pile group is, the smaller the pile group effect is.