新线、帮宽及既有高铁路基系统的沉降及稳定性研究OA北大核心

To guide the design,analysis and evaluation of the new-old subgrades interaction system formed by subgrade widening construction,the settlement,uneven settlement and stability characteristics of the system are investigated using the in-situ measurement and finite element analyses based on the engineering background of a newly constructed,foam concrete widened and existing subgrades system of the Hangzhou-Taizhou Railway in Wenling city of Zhejiang province.The measurement shows that during the initial construction stage of the new subgrade,its foundation settlement is greatly affected by the construction load and exhibited certain local rebounds and fluctuations.Whereas,the rebounds and fluctuations gradually are reduced with the increase of the subgrade filling thickness,and the final difference between the simulated and measured settlements is less than 5％.During the lightweight foam concrete widening construction,the maximum settlement position of the existing subgrade gradually is transitioned from the center of the subgrade surface to the junction of the existing and widened subgrades,and the settlement of the existing subgrade is less than 2 mm,where both the settlement and its rate are much less than the alarm values.After widening construction,the existing subgrade would experience a long-term consolidation settlement period due to the consolidation behavior of the soft subsoil,and the subsequent consolidation settlement could account for 71.4％of the final settlement.The foam concrete widened subgrade causes slight inclinations of the existing and widened subgrades(inclination ratios were less than 0.05％),which would not affect the smooth operation and normal drainage function of the existing and widened subgrades.The berm effect of the existing and widened subgrades results in the presence of the potential sliding surface of the whole subgrade system on the far side slope of the newly constructed subgrade.