Research On Comprehensive Treatment And Safety Evaluation Of Hamushan BarrierLake

“5.12”Wenchuan Earthquake created not only a large number of collapse and landslide hazard in the earthcquake affected areas,but also many dammed lakes formed by landslides blocking the river in the core area,especially for Hamushan Barrier Lake.Once the weir was broken,the rapid discharge of the lake would directly threaten the safety of the people in the Aba Tibetan and Qiang Autonomous Prefecture.Therefore,it is urgent to carry out the safety assessment on the Hamushan Barrier Lake and take measures to control it.In this paper,the multi-year average runoff depth,design flood,flood and dam-break flood are calculated at the dam site of the Hamushan Barrier Lake.According to the dam break flood peak flowand and the corresponding water level,we analyzed the Hamushan Barrier Lakedam break risk.Combined with geological condition ofthe dam foundation and dam abutment,we evaluated the safety of the dam foundation and dam abutmen.There is a leakage problem in the weir body,and there is a problem of the permeability around the steep slope.There may be uneven subsidence at the interface between the gravel and the bedrock.There is a problem of dam foundation leakage.Along the steep slope of the river,there is a problem of infiltration stability.The left abutment is stable,The right bank abutment is collapse accumulation body,the two sides of the abutment face penetration problem.In this paper,empirical analysis and planar two-dimensional finite element numerical analysis are used to analyze the seepage stability of the dam body.The calculation results show that the infiltration stability of the upper and lower reaches of the dam is satisfied.And the infiltration and stability of the dam along river are not satisfied,which are supposed to be carried out anti-seepage treatment.The high slope of the right bank of the dam has the instability of the slope of the P1 fracture zone;the right bank high slope H01 is unstable;H02 potential slippage instability is a total of three major security risks.H02 potential slippery body is instable,which exist three major security risks.In the end,according to the safety evaluation results of theHamushan Barrier Lake,the paper puts forward the comprehensive measures for the problems existing in the Hamushan Barrier Lake.Through the scheme comparison,the reinforced concrete cage is used to control the main river bank,we use masonry retaining wall to reinforcethe right bank.we use the retaining wall combined with the top of the roof excavation reinforcement program to deal withthe right bank loose bulk,which prevent the landslide completely blocking the tank.This paper is a practical case for the safety assessment and management of the dammed lake in China,and has some reference value for the construction of other similar projects.At the same time,it further consummates the theory and method of safety assessment and management of the barrier lake,and has certain academic value and engineering value.