Research on Pressure of Dike Leakage Hole Inlet Closure

Abstract

When the leakage inlet of a levee embankment is sealed, a transient flow similar to "water hammer" occurs, and the instantaneous cyclic changes in pressure can cause deformation or damage to the sealing material. At the same time, it can cause the alternating expansion and compression of the soil in the inlet section, which can further intensify erosion and collapsing, and lead to secondary damage to the leakage. This paper regards the sealing of levee embankment leakage as a valve closure operation of a thick-walled pipe inlet section, and based on simulation calculation methods, analyzes the pressure of sealing blockage at floodgate leakage inlet. The simulation results show that the pressure peak value appears at the inlet of the leakage, and the instantaneous pressure at the hole gradually decreases in a periodic trend. When the water depth at the inlet is 2.0m, the instantaneous static pressure of the seal drops from 1.05atm to 0.02atm and lasts for about 0.25s. Within the next 0.61s, the pressure continuously increases to a maximum value of 2.0atm. The first cycle of pressure change is about 1.62s, and the average cycle is about 1.20s. In order to ensure the success rate of sealing leakage, the water hammer pressure generated by the instantaneous sealing should be reduced, and the pressure that the sealing materials and equipment bear should be reduced or dispersed. Based on this, the concept of "step-by-step sealing" inside the hole is proposed, instead of single-level sealing of the hole.