Abstract: A GDS dynamic triaxial testing system was used for cyclic loading test to study pore-water pressure behaviors in tailings silt. Cyclic stress was applied to liquefy the tailings silt. The influences of relative density and confining pressure on pore-water pressure in tailings silt were studied. The results showed that the development of pore-water pressure can be divided into four stages， namely rapidly growing stage， stabilized-increasing stage， structural failure stage and fully liquefied stage. The increase of confining pressure and relative density can strengthen the capacity of anti-liquefaction. The result of lab tests on tailings silt was compared with that on sand， it showed that the characteristic of dynamic pore-water pressure for tailings silt is different from that of sand， and it can be described with a double-S model which has a very good application in both tailings silt and sand.

Key words: tailings silt, pore-water pressure, model, cyclic loading, dynamic triaxial test