Experimental study on water transfer of soil-rock mixtures under freezing action

The frost-heaving failure of earth-rock dam slopes is mainly caused by the combined action of sand and gravel cushion, frost heaving of dam fills and water migration. Aiming at the common frost-heaving damage problems such as uplift, dislocation and collapse of earth-rock dam slopes in cold areas, taking the sand and gravel cushion and dam fills as the research object, a self-developed water-transfer freezing test system for the earth-rock mixtures is used to carry out a one-way freezing model test study under water refill conditions. The effects of temperature, rock content and water migration on the frost-heaving characteristics of the soil-rock mixtures for slope protection of earth-rock dams are studied. The results show that the temperature and stone content have significant effects on the frost-heaving characteristics of the soil-rock mixtures. The water migration is affected by the soil and rock content, temperature and water content. The larger the water content of slope protection sand and gravel and dam fills, the greater the water migration during freezing, and the more sufficient the conditions for water phase to become ice. The stratification of soil and rock has a great influence on the soil temperature. The stratification of soil and gravel can effectively reduce the water migration and frost heaving, which is beneficial for the slope protection and frost-heaving prevention of the earth-rock dams. The main reason for the increase of the frost heaving is that the pore water phase in the soil-rock mixtures becomes ice and forms segregated ice in the samples. The in-situ frost heaving of the soil-rock mixtures and the growth of the segregated ice during the freezing process make the frost-heaving amount increase continuously. The freeze-heaving quantity of the samples under different temperatures and rock contents basically increases linearly with the increase of the water recharge, and the different rock contents have small effects on the rate of the freeze-heaving increase, while the different temperatures have a significant effect. The researchresults provide a scientific basis for the slope protection design and operation management of earth-rock dams in cold areas, and supplement the slope protection design in the design specifications of rolled earth-rock dams.