Analysis On The State Of Seepage Field For A Concrete Gravity Dam Foundation

For monitoring dam foundation seepage condition of hydropower project,to forecast the future development of the situation of the dam foundation seepage field,and to prevent dam foundation seepage failure and instability of dam,will in some part of the dam foundation embedment more instrument for monitoring displacement,uplift pressure and temperature,etc.,through the feedback from monitoring instrument,can understand each measuring point displacement change,real-time temperature and real-time uplift pressure,etc.,so as to get a general idea of dam foundation seepage field.Through the analysis of the measured data of typical dam section of the sequential process line and stepwise regression analysis,and seepage numerical simulation analysis being done on the basis of the typical dam section of the actual situation,the main research results and conclusions are as follows:(1)Dam foundation seepage field distribution of the typical dam section: the overall flow is from low to high.Obviously,near the bottom of the upstream curtain,have around seepage phenomenon;the seepage phenomenon in the bottom of the downstream curtain is relatively weak.In the effect of variable,the influence of the upstream water level for dam foundation seepage pressure is bigger;the influence of temperature and precipitation for dam foundation seepage pressure is small.Water storage affect in deep rock dam foundation seepage pressure greater than osmotic pressure of dam foundation,osmotic pressure close to the upstream greater than the osmotic pressure near the downstream,osmotic pressure measuring point near the drain less than measuring point away from the drain.The implementation of the drain can reduce the effects of water storage for dam foundation uplift pressure.(2)In the seepage numerical simulation,using kriging interpolation method based on the theory of regionalized variable to assign for dam foundation seepage coefficient,is to be able to assign values to the corresponding field water pressure test data on the grid cell,improve the parameters and the actual situation of compatibility,greatly improve the accuracy of the numerical simulation.(3)In the case of drain,in addition to osmometer PH-1,dam foundation uplift pressure for typical dam section of the seepage control measures are not sensitive,and it is reflected from the side,with a drainage system for dam foundation seepage play a part in controlling.Without drainage condition,the typical dam section dam foundation uplift pressure,for the rest of the seepage control measures except for consolidation grouting,are sensitive,the most sensitive is the permeability of the upstream curtain.