Permeability characteristics of cement-gravel soil

The triaxial permeability tests on cement-gravel soil are conducted using the improved triaxial test apparatus. Various factors including cement mixing ratio, gravel content, degree of compaction and seepage pressure that have effects on the permeability characteristics of cement-gravel soil are analyszed and discussed. The results show that the permeability resistance of cement-gravel soil is improved significantly with the increase of the cement mixing ratio. The permeability resistance of cement-gravel soil satisfies the requirements of core wall of earth-rockfill dams in the range of 30% ~ 50% of mixed gravel. Under the same mixing amount of gravel, the permeability coefficient of cement-gravel soil decreases with the increase of the degree of compaction. The permeability resistance of cement-gravel soil is greatly improved with the compaction degree of 98%. Under the same stress state, k₂₀-P curve meets hyperbola model, and the hyperbola model can be converted into the linear relationship between P/k₂₀ and P. The results can provide technical support for the permeability characteristics of cement-gravel soil applied to the core of high earth-rockfill dams.