Study On Mechanical Behavior And Design Optimization Of New Piles Foundation Cantilever Retaining Structure On The Slope

By the limit of topography and engineering cost, more and more subgrade with high filling soil and vertical slop appear in Chinese railway construction. Oridinary railway supporting and retaining structure can not meet the requirements of slope stability and deformation requirement of substructure, so a new retaining structure that can apply to this special terrain and meet the requirement of design life is to be put forward. The new piles foundation cantilever retaining structure has the features of cantilever retaining wall and piles foundation trimmer beam retaining structure. It not only meet the deformation requirement of high filling embankment, but also play a part in ensure slope incline and diminish filling soil. Because this structure is firstly applied to the railway project practice, its mechanical behavior and deformation characteristic are not definite, study on mechanical behaviorand design optimization of the new piles foundation cantilever retaining structure is a very urgent task.Firstly, based on piles foundation cantilever retaining structure of Lanzhou-Chongqing Hechuan station, the domestic and foreign current state of retaining structures on high filled ground subgrade is fully investigated. Referred to calculation theory of cantilever retaining wall and double-row piles trimmer beam retaining structure, the piles foundation cantilever retaining structure is devided to cantilever retaining wall and piles foundation trimmer beam retaining structure and caculated. Besides, a new calculation theory which can be applied to the piles foundation cantilever retaining structure on the high filled ground slope is put forward and analytical solution is obtained.Secondly, ABAQUS, which is a nonlinear finite element analysis software, is adopted and a three dimensional finite element model is established. The internal force distribution and eformation characteristic of new piles foundation cantilever retaining structure on subgrade slope with high filling soil are analyzed. The pile-soil and board-soil interactions are simulated by penalty contact. The size distribution characteristic of pile-soil and board-soil interactions is analyzed, which is contrast to theoretical calculation in order to verify the accuracy of theoretical calculation. Besides, models with different structure type and different row spacing and different anchorage depth and so on which are sensitive parameters are effectively analyzed in order to provide theoretical support for future structure design.At last, based on SAP2000, the new piles foundation cantilever retaining structure of Lanzhou-Chongqing Hechuan station is structural designed. The structure is optimized based on different conditions, and the suitable structure size parameters are put forward.Based on upper analysis, the mechanical behavior and deformation characteristic and design optimization of the new piles foundation cantilever retaining structure are analyzed and discussed. A set of calculation theory is put forward and structure size parameters are optimized in order to provide references for popularization and application of the structure.