Безопасность работы плит крепления нижних бьефов гидротехнических сооружений

Abstract

The purpose of the research was to study the conditions for maintaining the stability of the fastening plates under the infl uence of the hydrodynamic load in the downstream, ensuring the safety of its operation. Emergency situations at hydraulic structures often occur due to the loss of stability and subsequent destruction of fastening plates in the downstream of structures, which require signifi cant costs for their reconstruction. Ensuring the reliability and safety of the fastening plates of the downstream of hydraulic structures is closely connected with their stability during operation. The main reason for destruction of the fastening plates of the hearth and apron is the effect of the hydrodynamic load on them during the operation of the hydraulic structure. The methods for calculating the structures of the downstream fastening, providing for the weighting of the fastening plates, do not fully guarantee their stability and safety. The internal structure of prefabricated fasteners, where individual elements are connected by fl exible ties, allow their insignifi cant vertical and angular displacements and create the possibility of some deformation of the fastening without destruction. The process of vertical displacements of fastening plates in the period of their oscillations under the infl uence of a hydrodynamic load, described by a second-order linear differential equation with variable coeffi cients and a random right-hand side, is considered. The method of numerical solution of the equation is applied. It was found that the mathematical expectation of the position of the slab is practically independent of the ratios of the natural vibration frequency of the fastening plates and the driving frequency of the load pulsation, as well as the variation of the damping coeffi cients. The research results make it possible to change the approach to the design scheme of fastening plates during design, to make a forecast of the state of stability of the fastening plates depending on the current hydrodynamic load, and to identify the moment of loss of stability.