Evaluation on wetting effect of loess high-fill embankment under rainfall and groundwater uplift

Abstract

Rainfall infiltration and groundwater uplift are major triggers for the wetting deformation of loess high-fill embankments (LHFE). Based on the in-situ monitoring data of Lvliang Airport, the wetting effect of high-fill projects of which were analyzed. The soil–water characteristic curve (SWCC), the characteristics of permeability and long-term wetting deformation of loess were determined by laboratory tests. Finite element computation was carried out to investigate the seepage regularity of a typical LHFE under different rainfall intensities and groundwater uplift heights, and the wetting settlement of LHFE was calculated with layer-wise summation method (LWSM). Results show that the proposed empirical model can well simulate the unsaturated properties and long-term wetting deformation of loess. The profile of moisture content below the surface of LHFE presents a Y-shaped pattern under considered rainfall intensities. The maximum infiltration depth declines at higher compaction degrees and the wetting settlement ratio due to rainfall infiltration ranges from 0.5% to 1.2%. The maximum wetting height grows linearly with groundwater uplift height, the higher the compaction degree of the fill, the lower the wetting settlement due to groundwater uplift. The wetting settlement ratio for groundwater uplift is changing from 0.4% to 6.0%, and is decreasing with the average compaction degree of the LHFE. The settlement caused by groundwater uplift is about three times that by rainfall infiltration. The principle focused on the ‘three surfaces and two types of soil’ of LHFE were suggested for reinforcement and drainage measures. The results will provide reference for wetting settlement prediction and control for LHFE projects in loess region.