Determination And Influence Research Of Pile Neutral Point Depth In Collapsible Loess

Loess in rainfall, soaking cases, the consolidation will produce collapsible, resulting ina greater impact on the friction resistance of pile foundation of bridge substructure determineloess and loess neutral position collapsible for affect the position of the neutral pointaccurately calculate significant frictional resistance in the pile.In this paper, taking full account of the loess water erosion and their own collapsible,through the establishment of load transfer function presents a side with a pile of soil and soilpile tip bilinear hardening model with wet mechanical model simulation of collapsible loess,according to the soil body is elastic-plastic state and stiffness coefficient selected to simulatewater collapsible loess consolidation characteristics. Make the force and displacementequations, and boundary conditions under continuous loess elastic and plastic limit statesolution of two differential equations corresponding use. Use a neutral position in the pileaxial force is greatest to determine the eigenvalues of pile-soil displacement is zero. Frictionof Pile charged with calculating the position of the neutral point using numerical methods.Collapsible Loess neutral position before and after the change were compared, and throughan engineering example loess collapsible front and rear analog state, with a simplifiedbilinear model formula for verification. Validate the usefulness and accuracy of the presenttheory.For the effect of pile group effect, the paper limit state equilibrium theory semi-empirical method to calculate the theoretical half-pile group interaction coefficients,arranged derived formulas for different applications through different piles. The impact andeffect on the pile group made a neutral location data fitting comparison. And through twoexamples of the results of projects abroad compared with the conclusions more consistent.