Ranking of influence factors and control technologies for the post-construction settlement of loess high-filling embankments

Abstract

Ground treatments and post-construction settlement (PCS) control technologies are hot topics within the loess high-filling embankment (LHFE) research area. Taking the test section of a high filling airport constructed on a thick loess foundation as an example, the creep behaviour of undisturbed loess and compacted loess under high-pressure and different initial conditions are investigated using laboratory tests. The Mod-Burgers creep model of loess is proposed; a FLAC-3D simulation study is conducted to explore the PCS of high fill embankment under different influence factors. The research results show that the proposed Mod-Burgers model and equivalent creep modulus clearly reflect the long-term deformation characteristics of compacted and undisturbed loess. The filling height has the greatest impact on the PCS of high filling body, the compaction degree and water content are the second most important influence factors on the PCS of the high filling body. The pile length and pile spacing are the third important influence factors on the PCS of the original foundation. For the construction control of an LHFE in the gully, different treatment methods should be adopted according to different functional zones. It is recommended to adopt the dynamic compaction method for shallow loess foundation, and the collapsibility of loess should be eliminated. For thick loess foundation, the vibrating sinking gravel pile method is well-suited for treating an original foundation with low water content; cement-fly ash-gravel pile and lime-soil compaction pile are suitable for treating an original foundation with high water content.