Abstract: Taking the tailing sand from Xishimen Iron Mine as test materials,the tailings dam model with indoor small scale was built through self-developed physical model testing device of tailing dam.Pressure tests result in generating a high pore-water pressure in tailing dam but have less effect on the increase and the scope of saturation line,which indicated that there is little risk of dam failure leading to the sand liquefaction due to the continuing piling.The monitoring results on the displacement of tailing dam showed that maximum deformation is located in the middle of the dam,and the region is the key section of the dam failure and taking engineering measures.There exists a critical height for the dam stability.When the dam height exceeds the critical height,the deformation risk will increase sharply,causing the instability of the dam.Therefore,the critical height should be paid full attention in actual projects,and the corresponding engineering measures should be taken.

Key words: Test material, Tailings dam, Physical model test, Stability analysis