Impulsive forces distribution along the sediment storage dam upstream face for different mud–rock flow unit weight

Abstract

Because of the huge damage caused by mud-rock flow for the downstream life and property, engineering prevention must be given. It is one of fast and effective measures to build sediment storage dams in the formation zone to the circulation area. Due to the undercutting, scour and impact effect of mud-rock flows to sediment storage dam foundation or the unreasonable reconnaissance design, sediment storage dams possibly cause damage in the design period. However, the impulsive forces of mud-rock flow are the main reason to lead the engineering control structures (sediment storage dams, drainage grooves and block structure of pipe group) to damage. It is very important to study the law of mud-rock flow impulsive forces, and it is of great significance to prevent the damage of sediment storage dam and provide data support and technical support for the construction of sediment storage dam. First, the distribution rules of the maximum and mean value of the impulsive forces of mud-rock flow for the sediment storage dam upstream surface were studied for four mud-rock flow slurry unit weight as the experiment variable. The mud-rock flow impulsive forces value was collected by a numerical collection device that connected eight pressure sensors positioned in various locations, which received the mud-rock flow impact signal. Then, the distribution roles of the maximum and mean impulsive forces value imparted by water or water-rock flows were compared. The results indicate that (1) due to the randomness of particle impacts, the distribution law of the maximum impulsive forces is not obvious, and the maximum mud-rock flow impulsive forces of 99.277 kPa occur in A(1)B(3)C(7) (for a range of particle sizes of 2-4.5 cm); (2) the mud-rock flow impulsive forces mean value first increases and then decreases as the unit weight of the mud-rock flow increases; and (3) the mud-rock flow impulsive forces mean value gradually decreases along the height direction of the sediment storage dams' upstream surface and gradually decreases as the direction changes to the overflow section toward the dam abutments.