Effect of microstructure properties on of dynamic residual deformation behavior of saturated loess

Based on the SEM tests and dynamic triaxial tests on the loess with different microstructures from the Loess Plateau region and the liquefaction tests on undisturbed and disturbed Lanzhou loess with the same property state, the influence rules of structural properties of saturated loess on liquefaction strength are obtained. The relationship between microstructural types and the dynamic residual deformation behavior of saturated loess are qualitatively and quantitatively analyzed. Moreover, the development mechanisms of the dynamic residual deformation of the loess with different microstructures are obtained through analysis of the dynamic stress-dynamic residual strain of the loess in different regions. The results show that the liquefaction strength of saturated loess relates to the micro structure. The liquefaction strength of the soil decreases during the disturbed process because the particle reorganization and the cementation are weakened. The dynamic residual deformation of the saturated loess exponentially increases with the increase of vibration times, and the fitting parameters are mainly controlled by the density and plasticity index of the loess. The increase of dynamic residual deformation closely relates to the microstructural properties, the higher the structural strength, the slower growth the dynamic residual deformation of the loess. The development mechanisms of dynamic residual deformation are different for the loess with different microstructural properties. The dynamic residual deformation of weak cementation loess can be divided into visco-elastoplastic and plastic stages. However, the dynamic residual deformation of stronger cemented loess can be divided into visco-elastoplastic, visco-plasticity and plastic stages successively during liquefaction.