The Finite Element Static And Dynamic Analysis Of A Concrete Gravity Dam

Gravity dam is a kind of water retaining structure constructed with large volume of concrete or masonry, It’s typical section is shaped as triangle while the whole body is composed of several dam monoliths. Gravity dam in water pressure and other external loads, mainly depends on the self weight of dam body and cohesive force with base rock to produce the anti sliding force to maintain stability, and to offset tensile stress caused by water pressure to meet the strength requirements. Because of its relative safety and reliability, good durability, resistance to leakage, flooding, earthquake and war damage ability is strong, the design and construction technique is simple, strong adaptability for different terrain conditions, easy mechanical construction and other advantages, it is widely used in water conservancy and hydro power engineering construction. According to statistics, in the countries gravity dam often takes a large proportion in all kinds of dam type. For example, in China’s all kinds of higher than 100m dams those have been constructed or being constructed, there are 73 concrete gravity dams and take the proportion of 34%.The water retaining structure is the key to the construction of a hydro power station, its safety and stability influences the safe and stable operation of hydro power station, especially in high intensity earthquake area, dam structure of high stability, high strength is put forward higher requirements for the design and construction of the dam. This paper make studies on a Laos normal concrete gravity dam by using the traditional method of material mechanics and finite element method for researching the stress, deformation, anti-sliding stability and seismic safety. This paper mainly studies the following two aspects(1)Evaluate the strength and stability against sliding safety by using the method of material mechanics on stress, displacement and stability analysis of typical gravity dam section in plane strain condition(2)Based on the finite element method, studied the gravity dam in static, under strong earthquake stress state, deformation, stability against sliding and its self vibration characteristics. Carried out special study on dynamic analysis of dam body by mode superposition response spectrum method (2D) and time history response method (3D).Research shows that:The base bearing capacity of upstream tensile and downstream pressure stresses, the concrete strength of dam toe and heel, the anti sliding stability between concrete layers and concrete to base rock of this normal concrete gravity dam under static loads condition are meet specifications’ requirements. The reasonable distribution of stress and displacement of dam body complied with distribution of the cantilever beam in general. And after computation, it indicates that calculation results of stress and anti sliding stability of material mechanics method are conservative than those of finite element method. Under dynamic loading, it satisfies the requirement of dam safety. It can not only ensure the safety of structure under usual circumstances, but also avoid the formation of the so called "frequent incentive, infrequent response" and guarantee enough safety during an earthquake. The study results have certain reference value for engineering design.