The seepage and stability analyses for Gouhou faced rockfill dam was conducted using unsaturated soil seepage and strength theory.In the calculation

the hydraulic condition of seepage computation had been used in the stability analysis.The new conclusion provided a reference and complement for the former related research.The conclusion were: the hydraulic anisotropy caused by stratification elevates the height of phreatic table in case of steady seepage

however the safety factor will increase because of horizontal drainage.When the crack between the face and the material resulted in an abnormal seepage

the flow exited from the top of the dam

the top of the dam also was saturated

however the unsaturated zone still existed in the middle of the dam

the additional value of pore water pressure would not affect the slope stability so much.If the pore pressure was determined by the highest phreatic table as hydrostatic pressure

the stability analysis would obtain a wrong result.According to the calculation result of seepage and stability

the additional pore pressure from abnormal seepage would not lead to downstream slope failure

while the seepage failure on the top of the dam caused a local collapse and resulted in the breach at last.