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Occurrence of landsliding on slopes where flowsliding had previously occurred: An investigation in a loess platform, North-west China

Xu, L., Dai, F.C., Tu, X.B., Javed, I., Woodard, M.J., Jin, Y.L., Tham, L.G.
Catena 2013 v.104 pp. 195-209
deformation, irrigation, loess, mathematical models, shear strength, shear stress, soil, water content, water stress, China
Loess slides in South Jingyang platform, Shaanxi Province, usually occur on slopes where loess flowslides had previously occurred. Numerical modeling shows that flowslide occurrence causes conditions that increase shear stress and water content in the subsequent slopes. Both of these factors move the soil stress states towards its theoretical failure line. Under these conditions only small increases in water content can cause soil collapse. This leads to the backscarps of former flowslides being much more prone to landsliding. Wetting test results show that the loess can collapse suddenly as the water content gradually increases. Therefore, the wetting process induced by continued irrigation may result in the subsequent slides. During constant water content tests of the loess material soil shear strength increases with the development of specimen deformation. Therefore, slide mobilization, which may be a relatively slow process, is dependent on whether the wetting conditions exist. Finally, a slope evolution model for loess platforms is proposed in this study.