Studies On Thermal Fracture Problems In Concrete Dams Based On Scaled Boundary Finite Element Method

The temperature cracking caused by temperature changes that is the main reason of concrete gravity dams.The dam body has temperature change under the action of reservoir water temperature,atmospheric temperature,solar radiation and hydration heat of concrete,and then forms a temperature stress field in the dam body.When the ultimate tensile strength is greater than that of the dam,the cracking of the dam produces temperature cracks.This situation reduces the stability of the structure and threatens the structural safety.Therefore,it is very important to study the fracture of the concrete dam under the temperature load.Thermal load can lead to cracking of structure and thus seriously influence the stability of the structure.A numerical model for the thermal fracture analysis is presented based on the Scaled Boundary Finite Element Method(SBFEM).The temperature distribution is solved via the SBFEM,then the corresponding thermal load is divided into several items in the form of power functions,and the structural response is further obtained based on the principle of linear superposition.In the presented model,only the boundary of the structure is discretized,the temperature,displacement and stress fields can be obtained semi-analytically,thus the stress intensity factors are solved with high precision.Polygons are introduced in the generation of mesh and remeshing process during the crack propagation,so the time cost on dealing with the mesh is reduced to the minimum.The model is validated through the analysis of several plates and a crack trapezoidal dam.Considering the reservoir water temperature,air temperature,solar radiation boundary conditions,this model is applied to trapezoidal dam and Kelasuke gravity dam the numerical analysis of temperature fracture that analyses the temperature field,displacement field,deformation figure and stress intensity factorand.Temperature rise and temperature drop are analyzed.