The Stability Analysis And Engineering Technology Research On F₆₇ Fault Dams Of Fengman New Gravity Dam

Concrete gravity dam is the basic water-retaining structure, how to take appropriate technology to ensure the safety and stability of its basic with the different geological conditions is not only an important issue in the engineering construction but also the chief problem that must be solved in engineering design and construction.The comprehensive goverance engineering of Fengman hydropower station aim of building a new gravity dam in the lower reaches of the 120 m. The geological report indicates F67 fault fracture zone is located at the right bank of the new dam sit area. This fault must be processed because its exist threats the stability and operation security of the dam while the #29 to #32 retaining dam section of the new dam are constructed on the F67 fault fracture zone in the construction.Based on the design task of Fengman hydropower station reconstruction that China Water Northeasten Company undertaken, taking the concrete gravity dam as the research object, the foundation stability analysis methods and foundation processing technology of the concrete gravity dam were matered via the comparative analysis and researches of six constructed gravity dam with Annsha hydropower station dam included. On this basis, four kinds of engineering measures were comparative studied and then the measure of backfilling concrete after excavation in the foundation was chosen to process the F67 fault with the consideration of the geological condition and engineering characteristics of Fengman dam site area. Then the ultimate limit states design expressions were applied to make anti-sliding stability calculation of the foundation after procession, at the same time, the general finite element software ANSYS was used to make comparative analysis to the inhomogeneous deformation and stress of the fault dams and foundation under the working condition of finish time before and after the foundation procession, normal pool level and check flood level.The results show: the biggest inhomogeneous deformation of the fault dams and foundation is reduced 33.3% ~ 45.1%, while the reducetionof the maximum tensile stress of dams is 62.1% and the reduction of maximum compressive stress of foundation is 59% ~ 59%, it is visible that the inhomogeneous deformation and stress of the fault dams and foundation are reduced significantly after the replacement of concrete in the foundation. Besides, the inhomogeneous deformation and stress are all within the scope of the specification under various working conditions with no wide range of stress levels. The processing depth and length F67 fault can meet the requirements of the deformation and stress of dams and foundation, the engineering measures are reasonable and feasible.