Analysis Of Static, Dynamic Calculation Of Lijiaxia Arch Dam

Arch dams are widely used in hydropower projects in the world because of its light structure, beautiful shape, savings of engineering quantity, strong overcapacity and good aseismic performance, etc. With steady advancement of the western development and "electricity transmission from east to west" strategy, a number of high arch dams will be planned and constructed in deep valleys of west and southwest regions. The arch dam is a sort of space shell structure with complicated shapes. The stress level of dam body and the stability condition of abutment rock are the two key indexes to evaluate the safety of arch dam. In order to accurately grasp stress conditions of arch dam, the stress analysis means and calculating theory are explored and researched by technical and engineering sectors at all times so as to make them perfect and ensure the application of arch dam techniques in hydropower projects. The stress analytic method of arch dam covers pure arch method, arch beam sharing method, finite element method, calculating method of shell theory and structural model test method. At present, arch beam sharing method and finite element method are widely applied to calculate stress of dam body in the world. The main criterion of dam safety evaluation is on the basis of arch beam sharing method stipulated in the current Chinese Code of arch dam.Combined with basic shape of concrete double arch dam during construction and design periods, aiming at basic shape upon completion of arch dam foundation excavation and variation of geological conditions, and considering the difference between the gemel arch elevation, grouting temperature during stage impoundment & construction process and the original design, the static & dynamic stresses and displacement calculations under varied load combination conditions were obtained by arch beam snaring method and finite element method, etc. The static and dynamic stresses were analyzed and checked, and were compared with stress analysis results in the contracting design stage. The distribution regularity of stress and varied features for high arch dam were preliminarily discussed and the safety of dam body was comprehensively evaluated.The calculating results reveal that distribution regularity of stress is in conformity with that of the contracting design stage for Lijiaxia arch dam. The stress of arch dam shall meet the Specifications in respect of basic shape variation upon dam foundation excavation, varied module reduction on banks, staged impoundment and construction process, variation of local temperature field as well as jointing grouting elevation. It shall check aseismic performance of arch dam by pseudostatic method and dynamic method, and the dam stress shall meet the stipulations of the Code.