Tests on horizontal residual stresses of compacted clay and sand

Due to friction and biting between soil particles, residual stress will be generated after compaction. A set of horizontal residual stress testing device for compacted soils is designed and processed, which includes preparation of soil samples and loading. An experimental study is developed on the variation of the horizontal residual stresses of silt clay and sand with water content and compaction density. Then the horizontal residual stress characteristics of two typical roadbed filling are compared. Based on the Mohr-Coulomb criterion, a method for estimating the horizontal residual stress of compacted soil is proposed, which takes the characteristic components of shear capacity of soils c_m and φ_f as the core parameters. Finally, an error analysis is performed on the estimated results. The research shows that the compacted silty clay samples have a strong frictional locking effect between particles. The horizontal residual stress decreases approximately linearly with the increasing water content and shows a trend of increasing polyline acceleration with the increase of compaction. The sand samples prepared by the vibration compaction method have a small contact force between the particles, but their horizontal residual stress increases significantly after loading and unloading static loads, and it increases approximately linearly with the increase of water content and relative density. The horizontal residual stress of the compacted silty clay is significantly greater than that of the uniformly graded sand. According to the proposed analytical model, the estimated values obtained are in good agreement with the test ones, the average error of the silty clay samples is about 6.30%, and that of the sand is about 17.80%.