Study Of The Settlement Characteristics Of Composite Foundation With Long-short Piles Under Fill Embankment

With the high-speed railway construction started off, especially railwaytechnology without a frantic jumble applying in the large scale of high-speedpassenger railway, the higher deformation controlling requirement was put forward,mainly including the total settlement control and post-construction settlement control.Because of the advantages of composite foundation technique with long-short piles incontrolling settlement and saving cost, engineering has gradually spread thecomposite foundation with long-short piles from the civil building to the railwayengineering.However the existing settlement deformation theory of composite foundationbased on settlement deformation consistent of pile-soil is suitable for the compositefoundation under rigid foundation. There is difference between the measured valueand the calculated value using this stage of the composite foundation settlementdeformation theory, because the settlement deformation of pile-soil is inconsistentunder the flexible foundation due to the pierce deformation.Therefore, furtherresearch on the settlement character of the composite foundation with long-short pilesunder fill embankment has the important significance.This paper detailed researches two questions about the settlement calculation andsettlement prediction of composite foundation with long-short piles underembankment.First, study of the settlement characteristic of composite foundation withlong-short piles under the change of various factors, and determine the progression offactors using Grey Relative Model.Second, compares and analysis the existing calculation method and numerical calculation method of the composite foundation with long-short piles under fillembankment. Confirms the advantages and disadvantages of each method,determinesthe suitable method for the settlement of this engineering.Final, obtains the settlement regularity of composite foundation with long-shortpiles under fill embankment in loess area based on the field measured subsidence data.Compares and analysis the existing curve fitting forecasting method, confirmed thesuitable method for the settlement of this engineering. Put forward a method using ofthe least square method to deal with the observational settlement of not-uniform timeinterval.