Fluidization system for liquefaction tank

Abstract

For the experimental investigation of the static liquefaction of a slope of water-saturated fine sand first a uniform submerged sand layer is composed in a large liquefaction tank by applying fluidisation by upward flowing pore water from the bottom of the tank. Subsequently a submerged slope is created by applying hydraulic suction-dredging. Finally this submerged slope of uniform loose fine sand is loaded by inclining the tank and/or applying an impact load on the crest, inducing static liquefaction of the slope and a subsequent liquefied flow slide. In this paper the composition of the fluidization system is investigated, involving the required upward water flow, the internal diameter of the horizontal fluidization tubes for supplying the water, the diameter and distance between the lateral holes in the tubes for injecting the water into the sand bed and the water pressure of the supplied water to the fluidization tubes. For achieving a uniform sand bed, the fluidizing upward water flow must be practically constant along the full length of the horizontal fluidization tubes. To quantify the effects of the affecting parameters of the fluidization system, the water flow in the tubes is formulated mathematically, implemented numerically by applying the finite element method and quantified using a parametric numerical study. It is concluded that a set of horizontal parallel plastic tubes on the bottom of the tank at relative distances of 0.2 [m] in combination with the application of an input water pressure of only pin=50 [kPa] is suitable if tubes with internal diameters of D=40 [mm] are selected.