Methods for calculating the balance during the period of draw-off, drainage of sludge collector cells and construction of secondary embankment dams

Abstract

An industrial waste-phosphogypsum-is formed in the production of phosphorus mineral fertilizers. As is well-known, the issues of processing and utilization of phosphogypsum on an industrial scale remain unsolved. Consequently, production waste generated at chemical plants is stored in various types of storage tanks. The currently used hydraulic storage method provides for the supply of waste in the form of a slurry into the hydraulic dump cells, their sequential dehydration in the dump, and the subsequent development of a part of the stored waste for the construction of secondary dams. However, due to the low water-release properties of phosphogypsum, it is impossible to ensure its dehydration to the required degree, in large volumes, and the required period. Therefore, various designs of watertight diaphragms and drainage devices are provided in the sludge collector to accelerate the process of dehydration of the phosphogypsum strata. The balance of the sludge collector should be assessed in two periods: the initial period when the sludge collector cells are filled, bounded by the primary dam, and the subsequent period when the reservoir is built up by erecting secondary dams from the stored material. In the initial period, the operating mode of the sludge collector is divided into two stages: in the first stage, a pond is formed above the layer of sludge with a certain predetermined depth; in the second stage, this depth of water in the pond is kept constant by the spillways. The second build-up period is preceded by a period of cell preparation, namely: the draw-off of the pond and drainage of the cell to a moisture content suitable for the dam filling and normal operation of the mechanisms used in the construction of dams. This article presents the results of filtration studies in sludge collectors with an impermeable screen (made of polymer film, asphalt-polymer concrete, etc.) above the screen drainage system. The calculating methods for the determination of filtration parameters in the second period of operation are described: when the pulp supply stops, and a pond of clarified water with a depth of H0 is drawn off.

Investigation of nonlinear oscillations of high rise flue gas stacks under various kinematic effects

“…When solving the problem of unsteady forced vibrations of a rod (a structure), in addition to the boundary conditions, the initial conditions are also considered. The presented matrix system of differential equations (9), where the unknowns are the displacements of the connecting nodes of the rod elements, is solved by the Newmark step-by-step method [24]. This method is based on expansions of unknown node displacements q(ti+) and their derivatives ) (   i t q  into  power series (an integration step):…”

“…The dependence of the bending moment (M) on the curvature Then dependence (11) ceases to be linear       q q D q ) (   (24) where the matrix components   ) (q D q are power functions of the nodal displacement vector components, and its elements are determined by the following formula…”

“…By substituting (25) into (24) and, then, into (10), we obtain the stiffness matrix of the element, taking into account the geometric nonlinearity, which is the sum of the linear part (presented above) and the nonlinear part, depending on the longitudinal deformation acquired at each step and the change in curvature radius of the axis of the rod The resolving system of nonlinear differential equations obtained in the course of finite element discretization has the following form…”

“…As a result of the study, data were obtained on strains, stresses, accelerations, and force parameters of tall buildings under various impacts. The analysis showed a significant influence of geometric and physical nonlinearity on the dynamic response of high-rise buildings, which is important in the design and construction of such objects [24].…”

Horizontal and Vertical Movement of Concrete Dam Erecting on Sandy Soil under Seismic Loading

“…An experimental study of deformation and stability of dams built of phosphogypsum under seismic impacts, there was a consistent trend toward a particular reduction in the natural vibration periods of the models as the impact intensity increased. An increase in density could be the cause of this occurrence of the models' material and, as a result, a rise in their rigidity, [9].…”