Analysis and evaluation of seepage control monitoring of dam foundation during first impoundment period of a ultra-high earth rock dam

The evaluation of seepage control effect of dam foundation in the impoundment period is an important part of dam safety evaluation.It has significant meaning to summarize the seepage variation law of dam foundation during impoundment period for ensuring safe operation of ultra-high earth rock dams.Taking a 300m-level ultra-high earth-rock dam, Lianghekou Hydropower Station in China as an example, we analyzed and discussed the seepage control monitoring in the process of impoundment by analyzing the monitoring data and considering geological conditions as well as engineering layout.We ascertained the relevant problems and possible precautions and evaluated the engineering effect of seepage control measures.The result show that there is a certain correlation between the seepage pressure of dam foundation and the change of reservoir water level during the storage period, and the correlation effect only appears under the action of a certain water head.The change of seepage pressure of the dam foundation generally lags behind the change of reservoir water level.The deep seepage pressure of the dam foundation does not necessarily reflect the head or water level.The relevant experiences in this paper can provide references and ideas for subsequent similar projects.