Abstract: On the basis of monitoring data of Pubugou Hydropower Station during its impoundment,we analyzed the pore water pressure,soil pressure and the relationship between them in the core-wall. Results show that during the storage and discharge of water in the Pubugou Hydropower Station,the pore water pressure increases along with the rise of water level,and vice versa. The correlation between the water level and the osmotic pressure reduces from the upstream to the downstream ,and the reservoir water infiltration is the decisive factor of seepage water pressure variation in the core-wall. The variation pattern of soil pressure coincides well with that of pore water pressure. The adjustment of soil pressure value is jointly induced by water seepage and consolidation,which is mainly influenced by the water level in the upstream. During the reservoir impoundment,the effective stress drops,the percentage of pore water pressure in the soil pressure reaches 100%,and as the reservoir water reaches high level,local hydraulic fracture is likely to occur. The changjing laio of seepage pressure and soid pressure in the gravel soil core wall during the impoundment is summarized,similar projects as reference.

Key words: pore water pressure , soil pressure , effective stress , hydraulic fracturing