Influence of immersion depth of the sheet pile on the intensity of suffusion processes in pressure hydraulic structures

The research examines the influence of constructive features of a pressure hydraulic structure on the intensity of suffusion processes in the tailwater. The equations of non-vortex filtration fluid motion under a hydraulic structure in the form of a sheet pile wall are calculated by the finite element method using the Neumann and Dirichlet boundary conditions. The influence of immersion depth of the sheet pile on the erosion processes in the tailwater is investigated. The possibility of protecting the pressure head structure by creating an apron in the tailwater which prevents soil suffusion is analyzed. Calculations show that the greatest pressure gradients are observed at the sheet pile tip and at the outlet to the tailwater. From the point of view of the suffusion process, the zone at the lower end of the sheet pile is not dangerous; therefore, predictions about the suffusion intensity for a particular structure should be made on the basis of the output gradients at the tailwater border. Calculations show that the constructive features of a pressure hydraulic structure have a significant impact on the processes of suffusion and pile heave. The graphs are based on the calculation results; they clearly demonstrate that the filtration rate in the structure tailwater sharply decreases with an increase in the depth of driving the sheet pile, regardless of the soil type of the structure base. Besides, an additional protective effect is provided by a structure in the apron tailwater