A series of experimental researches of swelling pressure and swelling strain of bentonite-sand mixture are conducted by using self-developed swelling apparatus. Based on the experimental data obtained

the relationships between swelling pressure and time

vertical and horizontal swelling pressures

swelling strain and time

and swelling strain and water-absorbing volume are analyzed. The results show that the maximum swelling pressure and the maximum swelling strain of bentonite-sand mixture depend on the initial dry density and bentonite content of mixture

and increase with the increasing of these two factors. The increase of the dry density results in the decrease of the ratio of horizontal and vertical swelling pressures

and a linear relationship can be obtained between them. For bentonite-sand mixture with different bentonite contents

a hyperbolic relationship is obtained between swelling strain and time

and an approximate S-curve relationship is obtained between swelling strain and water-absorbing volume. Furthermore

the maximum swelling strain and bentonite content of bentonite-sand mixture demonstrate an exponential relationship. The experimental results are of reference value for design of buffer and back-filling materials in high-level radioactive repositories.