Stability Analysis And Reinforcement Scheme Research Of Homogeneous Earth Dam Based On Unsaturated Seepage

Some earth dams built in China in the last century have many problems,such as the filling compaction is not so good,dam foundation are not treated or treated improperly.After years of operation,all these result in some problems,such as dam slope instability,soil flow and piping of dam body and dam foundation,and even dam collapse accidents take place.In addition,the influence of unsaturated seepage is not currently considered in the earth dam design,and there is a large gap with the actual operation situation.Therefore,in the safety identification and hazard reinforcement design of existing dams,it is necessary to carry on unsaturated seepage analysis to seek reasonable and scientific hazard reinforcement scheme.In the design of earth dam,computational theory of saturated-unsaturated percolation shall be used to seepage and stability analysis of the dam.In this paper,as an example of Laobantian reservoir dam of Shilin county in Yunnan Province,the two-dimensional numerical simulation model was established by Geo-Studio software.Changes of dam infiltration line and seepage rules in different reinforcement measures(Conventional dam thickness,slope protection reinforcement,dam body filling grouting,dam foundation curtain grouting anti-seepage reinforcement,and clay paving reinforcement in the reservoir area)have been calculated and analyzed in different sections and different reservoir water level elevation by the SEEP / W module;Importing the results of the seepage calculation into the SIGMA / W module,the calculation and analysis of X-displacement,Y-displacement and X-Y displacement under different working conditions and different reinforcement schemes have been done by Mohr-Coulomb strength criterion;Importing the results of the seepage calculation to the SLOP / W module,the safety coefficients under different working conditions and reinforcement schemes have been studied.For Laobantian reservoir dam,in anti-seepage,conventional dam thickening and slope reinforcement + dam foundation curtain grouting + impervious clay blanket in reservoir bed has the best anti-seepage effect for the leakage of dam body and dam foundation;conventional dam thickening and slope reinforcement + dam filling grouting + dam foundation curtain grouting has the best anti-seepage effect for dam leakage;When the leakage is not so serious,conventional dam thickening and reinforcement may be a choice.In reducing displacement and deformation:conventional dam thickening and reinforcement,conventional dam thickening and reinforcement + impervious clay blanket in reservoir bed and conventional dam thickening and reinforcement + dam filling grouting + dam foundation curtain grouting are effective.In increasing dam stability,conventional dam thickening and reinforcement + dam filling grouting are best.