Study On The Bearing Characteristic And Ultimate Bearing Capability Forecast Of The Cast-in-place Pile With Branches And Plates

The cast-in-place pile with branches and plates is the new kind of pile invited in 1990s'. As a promising pile, setting the plates and branches neatly and making full use of every stratum with good mechanical characteristic are the greatest advantage, which are the reasons for the improvement of the single piles' ultimate bearing capability. Because of more complicated bearing mechanism than the ordinary one, the piles' ultimate bearing capability influenced by more factors. Hence, the study on the pile's bearing characteristics is an important question for discussion. On the other hand, it will be meaningful to the pile's study and application that a model or a method that can forecast the ultimate bearing capability and the whole P-S graph well and truly is found out.In this article, the pile's bearing characteristic under the vertical and plane load were researched by means of FEM, and a model, based on Least Square Method, that can forecast the ultimate bearing capability and the whole P-S graph were found. The main work is as following:Contrasted with ordinary piles with the same condition including stratums, load, and diameter, the cast-in-place pile's bearing characteristic under the plane load was analyzed by means of FEM. Through changing the plates-setting position, the position's effect on the pile's resistance capability to the plane load was researched and some suggestions for designing were brought forward. Furthermore, under the vertical load, the pile's bearing characteristic, load transferring mechanism, and some suggestions were advanced.Based on Least Square Method, the Hyperbola Model, Adjusted Hyperbola Model, Exponent Model, Grey model and est. were used to forecast the pile's ultimate bearing capability and P-S graph. In order to improve the forecast precision, the Grey Model was modified and a matlab program was written. After analyzing the models' characteristic, the most accurate model——Hyperbola Model was found and its applicability was proven by 54 piles experiment data from four provinces. Moreover, Hyperbola Model's characteristic and the method to improve its precision were analyzed.