Method for calculating foundation settlement of compacted backfill in hilly and gully regions of loess

The problem of foundation settlement control of high loess filled projects is important and difficult. Because of the lack of researches on methods for calculating settlement of compacted backfill foundation of high embankments in hilly and gully regions of loess, a series of indoor confined consolidation experiments using indoor artificial test samples and field samples are carried out. The deformation characteristics of compacted backfill loess are studied. Based on the different research paths of the secant modulus method and the stratified summation method, a modified foundation settlement method is proposed. The differences of the final settlements under different methods are compared and analyzed. The results show that the calculated values by the secant modulus method based on the vertical stress - strain relation of Gunary Model are smaller than those based on the stratified method, and the difference range is within 4.8%. The compactness of backfill loess is basically stable in (70±5) %. In fact, it is a very low compactness. The final compression and consolidation settlement of the 33 m-deep test site is predicted by the proposed method, and it is 1523.2 mm. The infrastructure construction in backfill area should be carried out after full consolidation of the foundation. In the meanwhile, the compactness should be strictly controlled during construction of high embankments, and the quality of construction should be improved. The new foundation settlement is a useful supplement to the computational system of secant modulus method in settlement calculation, and the calculated results are available to guide the construction and design of practical projects.