The initiation mechanism of loess collapses induced by salt erosion

摘要

The salt erosion occurring in loess area caused slope collapses frequently. The analysis for soluble salt in loess were conducted with 10 pairs of specimen collected from the toe of slopes nearby the collapses induced by typical salt erosion in the loess region. One of the each pair of specimen was taken from the corroded surface soil and another from the internal soil at the same site. The comparison of the data shows that the soluble salt content of corroded surface soil was obviously higher than that in the internal soil, so the initiation mechanism of the collapse is supposed that as the water with soluble salt migrates from lower to upper, soluble salt cluster in the toe of slope under the evaporation, then the structure of the loess was destroyed during crystallization of the soluble salt. The very thin particulate of disintegration loess continuously flaked from the surface, which result in the lower of slope recurring, and in turn, make that lost supports. Finally either topples or scattered collapse was triggered.