The Improvement And Implementation Of The Trial Load Method For Arch Dam Analysis By ANSYS

The trial load method specified by the present standard codes,is the most widely used method for the stress analysis of arch dams.In this dissertation,an improved multiple arch-cantilever method for the static and dynamic analysis of arch dam is proposed,which is also used by the finite element analysis software ANSYS.1.Based on the principle of loading distribution between arch and cantilever elements, using the finite element software ANSYS.an effective approach is developed with a compability of 4 arch and cantilever deflection components at their intersection points.It takes into account deflection coupling of arch-foundation-cantilever system through U-shape elements.It selects loading part assigned to the arch elements as the primary unknown variables to formulate the basic equations.The matrix flexibility of the arch and cantilever element is from the element software ANSYS.and with which the result can save effort.2.The geometry,shape of arch and beam is modeled by the beam element provided by finite element software ANSYS so that spatial distortional property of arch axis and cross-section change of arch dam can be model more accurately,where rectangular profile is usually assumed for the arch and cantilever method.The results show that the stiffness matrices and the stress fields of arch and cantilever elements are evaluated in a more rational way.3.The Vogt method is widely used in foundation computation,which is approximate.In order to improve the accuracy of trial load method,the Finite Element Method is employed to model the more actual arch dam foundation.Stiffness of foundation is calculated by Finite Element Method and the shape and the heterogeneous geology of valley are considered.The results show that the improved method combing with the finite element method can be applied to more complicated foundations.Meanwhile,a three-dimensional unbounded foundation model of arch dam was proposed by SBFEM,which make the interaction to arch dam by unbounded foundation was simulated reasonably.4.For the earthquake analysis of arch dams,the vibration modes of arch elements are chosen as the generalized coordinates to formulate the equations of motions of the dam,it reduce computational effort to a great extent,while necessary accuracy of the computation is ensured.