Nnumerical Analysis Of Seepage Flow And Stability Of Chaohe Main Dam Of Miyun Reservoir Safety Assessment

Miyun reservoir is a mainly flood control,water supply,power generation and fish and so on comprehensive utilization of a variety of functions,regulation of large water conservancy projects for many years,is the biggest reservoir in north China,after a total capacity of 4.375 billion m,is the source of drinking water of Beijing's most important surface.On September 11,2015,the Yangtze river was officially entered into miyun reservoir in the south-to-north water diversion project.The reservoir increased the water resources of the south-north water diversion project and realized the important role of Beijing's water resources optimization allocation.There are two main dams,five sub-dams,seven tunnels and one regulating pool.Among them,chaohe dam is one of the two main DAMS of miyun reservoir,which is one of the most important parts of reservoir retaining buildings.Tsinghua university in 1995 with the miyun reservoir safety appraisal,discovered that tidal river main 8 ° upstream dam slope safety factor when the earthquake,followed by a floating refueling,underwater riprap slope aseismic reinforcement measures.Twenty years ago,without excessive water level testing,and special safety evaluation,it is necessary to review key indicators such as seepage flow and dam slope stability.Based on the actual situation of miyun reservoir engineering,the paper analyzes and evaluates the safety of the dam of chaohe dam by analyzing the seepage flow and stable numerical analysis and safety evaluation.Through daily seepage,deformation monitoring data and professional geotechnical software GEO-SEEP/W and SLOPE/W in the studio,the QUAKE/W module for data analysis and numerical simulation respectively,from the dam seepage safety,dam SLOPE stability safety,such as the seismic safety for the safety evaluation,the results showed that:(1)the seepage monitoring equipment of chaohe main dam is fully complete and normal,and the seepage state generally meets the safety operation requirements of the dam.Alveolus seepage control of large hydraulic gradient area mainly in the interior,the largest hydraulic gradient is 5.0,less inclined wall hydraulic gradient is 0.52,seepage failure will not occur,the downstream seepage line position is lower than the design value,dam body inclined wall anti-seepage effect is apparent,the dam seepage stability.(2)the deformation monitoring facilities of the DAMS are arranged reasonably,and the variation of horizontal displacement and vertical displacement has stabilized.Unsteading infiltration water after the settlement,displacement and stress distribution is reasonable and accords with the general law of earth-rock dam settlement and stress level is within the scope of the security,site inspection found no obvious cracks and dam collapse.(3)the safety factor meets the requirements of the specification at the peak acceleration of 0.20 g.Specification under the action of wave,the relative horizontal acceleration and relative horizontal displacement reaches the maximum at the same time,the maximum relative displacement of the crest,mainly in the whole dynamic displacement is small,the deformation distribution in line with the general rules,have less effect on seismic performance of the dam body as a whole.(4)according to the guidelines for the reservoir dam safety evaluation and related technical specifications,with reference to the seepage safety,structural safety and seismic safety evaluation standard,the result is: the seepage safety-A level,structure,class A,seismic safety,class B,tidal river main operating normally.