Dynamic properties of Tianshui saturated remolded loess: A laboratory study

Tianshui City is located in an earthquake-prone area of China that has experienced many earthquake-induced loess landslides. The formation of such landslides is closely related to the dynamic properties and residual deformation characteristics of the loess when seismically loaded. However, the loess dynamics under earthquakes in the Tianshui area have been little studied. Therefore, to understand the dynamic properties of loess during the earthquake, consolidated-drained triaxial tests were conducted on saturated remolded loess specimens in GCTS cyclic triaxial WA system. The results indicate that (1) The dynamic properties of saturated remolded loess are closely related to the consolidation confining pressure, initial stress state, dynamic stress amplitude and N. The dynamic strength of loess specimens increases with increasing confining pressure but decreases as N-f and the consolidation stress ratio increase. (2) Isotropically consolidated specimens undergo tensile deformation and shear dilation, and the consolidation confining pressure has a significant influence on the accumulated residual strain. However, anisotropically consolidated specimens undergo compressive deformation and shear shrinkage, and the consolidation confining pressure has limited impact on the accumulated residual strain. (3) The dynamic elastic modulus of saturated remolded loess decreases with increasing strain and cycle number, and increases with increasing confining pressure. The damping ratio increases nonlinearly with increasing dynamic strain and decreases with increasing confining pressure. (4) There is a significant critical effect on the growth of residual deformation. After a certain critical N or dynamic stress, the accumulated residual deformation increases rapidly. Under isotropic consolidation, the specimens undergo shear shrinkage in the initial stage of cyclic loading, which gradually changes to shear dilation as the number of cycles increase. Under anisotropic consolidation, the specimens are basically in a state of shear shrinkage under cyclic loading. The results form an important reference for loess material, and are significant in terms of stability analysis of loess slopes and for improving the dynamic constitutive relationships in loess.