Study On Dry - Wet Cycle Characteristics Of Red Soil In Yunnan Bank Under The Action Of Reservoir Water

In recent years, Yunnan suffered general high temperature and drought, at the same time, as the time goes by the heavy rainfall in deposit lead to reservoir collapse and dangerous intensify is become more and more serious. This paper choose Kunming laterite type of reservoir bank slop, carry out the academic subjects of "Yunnan laterite type of bank erosion process studies". Around this theme, launched a laterite type of reservoir bank slope erosion model test and Wet-dry cycle characteristic test.With the model test showed us, the changes of water level lead to laterite earth pressure decreases, and pore water pressure increase. And lead to large particles of soil migrate to the upstream toe of the bank slop, and lead to the particle size distribution become more and more worse.The Wet-dry test showed us, as the Humidification time goes by, shear strength decreases rapidly first, after slowly rise, and eventually completely lost. As the Dehumidifying time goes by, the shear strength will be sustained slow recovery. The Wet-dry tests will lead to shear strength is reduced, and lead to compression performance become more and more larger, and the permeability increased.The microstructure characteristic test showed us, lower multiples magnifying in favor of mastering the soil loose and close degree. The large multiples magnifying in favor of observing the inside of soil and soil particles distribution. At the same time it can be observed the laterite inside circularity and particles complexity and other characteristic parameters. At the same time, with the extension of immersion time, the internal pores become more and more larger, and laterite particle surface more and more irregular. The higher temperature conservation role will greater porosity than low temperature and room temperature.With repeated cycles of Wet and dry, happening physical, chemical and mechanical action. The physical action included, softening, erosion, mudding and so on. The chemical action included, Ion exchange adsorption, isomorphous replacement effect, laterite minerals hydrolysis ionization and so on. The mechanical action included effect to shear strength, compressive properties and permeability.