Research On Scheme Comparison And Selection Of Deformation Reinforcement For Penstock In Hydropower Station

The penstock hydropower station is an important hydraulic structure in the water conservancy project,and it has experienced the historical processes from small to large,and simple to complex.With the construction of large hydropower station and high head large-capacity pumped storage power station,the stiffness of pipeline is more and more flexible,and the thickness is relatively thinner and thinner,making the penstock become a typical thin shell structure,so its stability is very prominent.Therefore,it is of great significance to analyze the instability buckling failure theory of penstocks under external pressure and to provide a set of feasible calculation methods for stability analysis,which instructs the reasonability of construction and takes appropriate reinforcement measures in the project,and further to satisfy the stability of structure.In this paper,the penstock of Yamadu(YMD)Hydropower Station is taken as an example to introduce the development and research situation of the hydropower station penstock,and the reinforcement plan of the penstock is expounded.The finite element model of two reinforcement projects for the stiffening ring of the penstock and the inner lining of the penstock is established by means of the large finite element analysis software ANSYS.This paper has calculated the previous model data,and the analysis of the ultimate bearing capacity,stress and deformation of each reinforcement project is carried out.Then we have selected among these projects.By defining different analysis paths,the stress and deformation distribution laws of two reinforcement projects for YMD hydropower penstocks are obtained.The analysis of the calculation results shows that the current situation includes the initial stress field and the displacement field.Initial defects and stress fields should be introduced when strengthening the penstock.With the increase of radial pressure,the maximum total displacement of the top,waist and bottom of the penstock is gradually increased,and the maximum Mises equivalent stress also increases gradually in the condition of the two reinforcement projects of stiffening ring and inner lining of the penstock.The reinforcement project of the stiffening ring of the penstock reaches the limit state of the bearing capacity at 1.9 standard atmospheric pressures,which deforms at 299mm at this time.However,the reinforcement project of inner lining of the penstock reaches the limit state of the bearing capacity at 3.1 standard atmospheric pressures,which deforms at 303mm at this time.The bearing capacity of the inner lining of the penstock is higher than that of the stiffening ring,so the reinforcement project of inner lining of the penstock is recommended.The research results of this paper provide a reference for the design and construction of buried stiffened penstock structure.