To research the effect of seepage on mesostructural change of soil-rock mixtures

a laboratory seepage test was applied on soil-rock mixtures with the ratio of 7:3. Nuclear magnetic resonance (NMR) analysis system was applied to monitor the mesostructure change of soil-rock mixtures under different hydraulic gradients and different time periods

such as pore distribution

movable fluid porosity

etc. According to NMR results

it was found that: 1) Seepage pressure caused change of soil-rock mixture properties such as pore distribution

pore size and pore connectivity

which can damage structural characteristics of soil-rock mixtures. 2) With the increase of hydraulic gradient and time

porosity

mobile fluid porosity and NMR permeability all increase

and the NMR permeability growth rate is increased. Besides

mobile fluid porosity has a more significant contribution to permeability than irreducible porosity. 3) Under low hydraulic gradient

the coefficients of Kua and Kca have small change

which reveals low erosion scales and low degree of seepage failure. Under high hydraulic gradient

the coefficients of Kua and Kca have significant change and erosion scales become higher. The soil-rock mixtures form seepage channel and seepage failure.