Determination of settlement parameters of highway embankment and base consolidation time depending on soil characteristics

Abstract

The paper proposes and implements a calculation and forecasting principle for designing a subgrade of fast-speed and high-speed highways on a weak foundation, and it is also proposed, taking into account a significant increase in the predicted values ​​of total deformations, to consider embankments with a height of more than 6 m on high-speed highways as individual design areas. It has been proven that in case of strengthening the subgrade foundation with CFG piles, the deformation characteristics of the soft soil of the space between the piles do not affect the amount of settlement and the time of consolidation. It is shown that the theoretical positions are confirmed by the results of numerical simulation. The necessity of keeping the embankments up to the construction of the track superstructure, even with the strengthening of weak foundations with composite structures, has been proved. Based on the results of the performed calculations, the area of ​​effective application of composite base structures with CFG piles for sections with a ballastless superstructure of the track, which provide the minimum allowable residual deformation during operation, was determined. Sand piles and Jet-Grouting piles can be effectively applied in composite subgrade structures of fast-speed and high-speed highways with a ballasted track structure. The influence of physical and mechanical characteristics and filtration properties of weak soil of the inter-pile space on the total amount of settlement and consolidation time was determined.