High-speed Railway Subgrade Settlement Testing And Analysis

The ballastless track of high-speed railway is strict with the settlement, it requires the post-construction settlement reach the "zero settlement" normative. Therefore, the settlement control technology of the subgrade settlement has become a key technical issue during the construction of railway subgrade in high-speed railway. Based on the field measurement, the settlement analysis and the numerical simulation, the subgrade settlement issue in Beijing-Shanghai high-speed railway have been analyzed. The main contents and conclusions as follows:(1) According to the technical requirements of settlement monitor in Beijing-Shanghai high-speed railway, the dynamic deformation monitoring in typical workshop section, mainly in An-Hui province, have been finished and the original data of the subgrade settlement versus times have been achieved.(2) The analysis and prediction for subgrade settlement in Beijing-Shanghai high-speed railway have been developed. And data fitting and forecast for posterior settlement have been preceded based on the field measurement technique and the original data of subgrade settlement in typical workshop section.(3) Based on the idea of robust regression, the objective function have been amended by M-estimation method during the data analysis for the abnormal values in the process of data analysis are very sensitive to the classical least-square regression. The outliers have been diagnosed and deleted and then they have been re-estimated by the least square method.(4) The settlement simulation analyses during the construction of roadbed filling on the top of the Cement Fly-ash Grave Piles composite foundation have been executed by using the FLAC finite difference program. Simulation results show that, the difference between the analog result and measured value is small under the conditions of layered filling and compaction; the simulation results reflect the change trends of subgrade settlement well.