Wuhan-guangzhou Passenger Line Embankment Settlement Experimental Study

Due to the rapidality and high technology standard of high speed railway and the strict requirement of its subgrade settlement, controlling the deformation of passenger railway line subgrade has been the most obvious characteristic. Wuhan-Guangzhou Passenger Railway Line is the first line in which ballastless track is adoppted in the whole line, so the research on the developing law and the mechanism of the subgrade settlement,accurate and timely compute the subgrade settlement will provide certain guidance for reasonably planning construction schedule and arranging paving time,meanwhile,the research has a great significance in guarantanteeing the passenger railway line's operational safety,reducing the cost of the line's operation and improving its economic efficiency.Based on the other reseacher's achievement, taking the Comprehensive Experimental Section of Wuhan-Guangzhou Passenger Railway Line as the project background,methods such as testing in the laboratory,monitoring survey in the field, theoretical analysis and numerical simulation,etc.were used in this paper to make a comprehensive, indepth research on the computation analysis and special characteristic of the passenger railway line's subgrade settlement.Its main achievement and tasks were generalized as follows:(1) On the basis of summarizing the existing study results,such as the formation mechanism,developing discipline and effective factors of the subgrade soil's settlement,the theory foundation, calculation steps and appliance condition of the existing methods to caculate the subgrade settlement were analyzed.(2) According to the site's geological conditions,foundation treatment and the designation of the passenger railway line,the monitoring sections,equipments and devices of the passenger railway line's subgrade settlement were choosed rationally,the monitoring cheme were reasonably determined.(3) Based on analyzing the work principle of the monitoring devices,specific protection measures and the equipments installation programs were put forward.After that,575 days observation of the eighteen monitoring devices were executed, a large amount of the field measurement date were gained.(4) Combined with the construction schedule,systematic collation and analysis of the field measurement date were done,the foudationg deformation of different subgrade types under distict construction stage were obtained,according to these results,the developing process and law of the passenger railway line's subgrade settlement was studied.(5) A series of laboratory soil tests on undisturbed soil samples were carried out,based on which the parameter was set up for the finite element simulation,more importantly,the strength properties under different consolidation degree and the rheological characters under long-term load of the subgrade soil were analyzed.(6) Mohr-Coulomb constitutive model was choosed to simulate the subgrade,the soil and the CFG piles,the interaction of contact between CFG piles,geo-grid and soil was simulated by Goodman interface unit without thickness,upon the completion of these work, the finite element numerical model was applied, the rationality of model and parameter were proved by comparing the measure results with the calculation.