Experimental study on the effect of fine particle loss promoting the wetting deformation of rockfills
Under situations of the periodical water level fluctuations,the fine particles in rockfills might be washed out,thereby promoting the wetting-induced long-term deformation of rockfills.To reveal the mechanism of the large long-term deformation of a rock-fill dam,a series of comparative oedometer erosion tests were conducted on the samples with both continuous and discontinuous particle gradations of the dam's upstream rockfill under con-stant and fluctuating water level conditions respectively.The histories of the axial strain and fine particle loss were recorded under different conditions.The comparative test results confirmed that the water level fluctuation can lead to considerable amount of particle loss and thus aggravate the wetting deformation,and the influencing extent de-pends on the particle gradation,surcharge pressure,the falling speed of water level and initial water content.The specimens of a continuous gradation are internally stable and exhibit smaller amount of fine particle loss than the specimens of a gap gradation,and consequently,fine particle loss has less significant effect on the wetting deform-ation.Higher surcharge pressure can reduce the promotion effect of fine particle loss on wetting deformation because of the less particle loss under the higher particle interaction forces.The fine particle loss increases with the increas-ing falling speed of water level,and therefore,larger wetting deformation was observed under the tests of higher water discharge rate.Increasing the initial water content will improve the compactness of the rockfill material,re-sulting in a tighter particle arrangement and difficulty in fine particle loss,thereby fine particle loss has less signifi-cant effect on the wetting deformation.
rock mechanicsrockfillwetting deformationparticle lossperiodical water level fluctuations
万方数据
维普
