Research On Seepage Characteristics Of The Right Bank And Its Influence To The Project Of Renzonghai Rockfill Dam

The maximum height of the Renzonghai rockfill dam is about 56 m,and the river bed in the dam site area is a thick overburden with a thickness of up to 130m-148 m.The dam body and dam foundation anti-seepage adopt composite geomembrane and suspended anti-seepage wall respectively,the maximum depth of the anti-seepage wall is 82 m.Because the cracks on both sides of the mountain are more developed,curtain grouting is used to prevent seepage.The anti-seepage curtain on the right bank penetrates into the mountain 107 m horizontally,and extends vertically from 2934 m to 2850 m in elevation.In the 10 years from 2009 to 2019,the rockfill dam has seepage around the dam and the dam has been in an abnormal state of leakage.Therefore,the monitoring data of the seepage around the dam on the right bank and three-dimensional numerical simulation are used to analyze Temporal and spatial characteristics,calculating the hydraulic slope of the dam profile,and studying the impact of leakage on the rockfill dam project,the following conclusions were obtained:(1)By analyzing the monitoring data of the five seepage pressure gauges in the lower bank of the right bank grouting,when the reservoir water level is 2930 m,the water level of the seepage hole located in the middle of the flat bank is the highest.And in the process of the reservoir water level rising from 2910 m to 2930 m,the seepage hole water level rise rate is the largest and has the best correlation with the reservoir water level.The infiltrated parts are mainly concentrated in the 0 + 40 m ? 0 + 90 m section of the lower flat.(2)According to the analysis of monitoring data and on-site investigation,it is found that the seepage at the foot of the slope behind the right bank and the lower gallery of the right bank and the water column of the exploration hole behind the dam are all caused by the reservoir water bypassing the right bank anti-seepage curtain and passing through the dam body to the dam After the dam on the right bank,the groundwater level rises,causing leakage.The leakage of the lower gallery on the right bank is mainly concentrated in the section of 0 + 90 m ? 0 + 300 m,and the leakage volume of the right bank increases year by year after 2013.(3)Using three-dimensional numerical simulation,the flow characteristics of the anti-seepage curtain and the groundwater behind the dam are simulated under two different depths of the right bank anti-seepage curtain,indicating that some groundwater is indeed seepage around the bottom of the anti-seepage curtain.The current flows from the right bank to the left bank.(4)By calculating the percolation slope of the effective monitoring data of the piezometer in the four monitoring sections of the dam body,the permeation slope each section is less than the allowable value,and the dam body infiltration line is low.Although the maximum leakage volume behind the dam on the right bank is 315.93 L / s,which is higher than other projects,the leakage water behind the dam is relatively clear,and no obvious sediment is brought out of the water,so the dam leakage has no destructive impact on the project.