The Research Concerning Pile-soil Stress And Settlement Of CFG Pile-raft Composite Foundation Of Embankment-bridge Transitional Belt

The High-speed railway makes great claims upon the stable comfort of line, the construction of high-speed railway with ballastless track puts forward higher requirements for the subgrade deformation of embankment-bridge transitional belt,the uniformity of stiffness and the stability of train operation and natural conditions. Therefore, making a good job in the interface of embankment-bridge transitional belt matters a great deal to improve the overall stability of high-speed railway.This paper focus on the control technology for foundation settlement combining with the engineering practice during the embankment-bridge transitional belt of the high-speed railway with ballastless track. This paper carries out the researchs through comprehensive research, field test, theory analysis and other different methods for different geological conditions, different site conditions including considering various factors in order to strengthen the observation and prediction of subgrade settlement deformation of embankment-bridge transitional belt of the high-speed railway with ballastless track. For the above-mentioned researchs, this paper try to make a thorough research on the mechanism and structure optimization design of foundation treatment measures during the embankment-bridge transitional belt of the high-speed railway with ballastless track.The CFG pile-raft composite foundation requires very complex consideration of the stress-strain relationship between the pile and soil and the foundation settlement laws, involving the complex interaction between the pile and soil. Currently, the research methods for CFG pile-raft composite foundation have three main categories, including theoretical formula method, field test method and numerical analysis method.The main research contents of this thesis are as follows:1) This paper introduces the advantages of CFG pile-raft composite foundation and the treatment application and research status during the embankment-bridge transitional belt of the high-speed railway with ballastless track.2) This paper make a summary of CFG pile-raft composite foundation settlement, the stress-strain relationship of pile body and the calculation of ratio of the stress between pile and soil,combining with the existing information and research outcomes.3) This paper selects the typical section of test site in Tianjin-Qinhuangdao passenger transportation line,then monitors the foundation settlement and stress between pile and soil during the embankment-bridge transitional belt according to the test scheme of embankment-bridge transitional belt of the high-speed railway with ballastless track. Then collects and analysises the test data,plots the trend chart of settlement deformation and stress-strain relationship, forecasts the settlement of embankment-bridge transitional belt based on gray theory, and then analysises the settlement laws of the embankment-bridge transitional belt based on these analysis of the results.4) This paper selects reasonable parameters and basic hypothesis established model through the ABAQUS finite element software,then analysises the effect of those factors of CFG pile-raft composite foundation on the settlement and stress-strain relationship.