Panel (30) presenting rectangular and / or square main surfaces (1) of flat material as plates for the wall of container covers or stable covers (40) that have the shape of a parallelepiped, preferably of a cuboid or of a polygonal prism, for material with flow capacity, granulated, lumpy and / or first with flow capacity and which then hardens, in particular perimeter walls of raised floor masonry beds or the like, - where on two of their opposite sides, parallel one with respect to the other, respectively, at least one other panel (30 ') designed in the same way can be connected laterally, forming a common vertical edge (45) of the wall of the container covers or stable covers (40) having the form of a parallelepiped, where the panel (30, 30 '), along the two other sides equally opposite each other, has reinforcing and joining strips (12, 12') folded at an angle of 90 ° from its s a main surface (1) in the same direction as the edge stabilization strips (11.11 '), characterized in that - along the two mentioned sides of the main surface (1) respectively an edge stabilization strip (11, 11 ') is bent at an angle corresponding to half the internal angle of the edges (α) of the respective parallelepiped, - the two edge stabilization strips (11, 11') are shortened at both ends in a value (b).Panel (30) que presenta superficies principales (1) rectangulares y/o cuadradas de material plano a modo de placas para la pared de cubiertas de contenedor o cubiertas estables (40) que presentan la forma de un paralelepípedo, preferentemente de un cuboide o de un prisma poligonal, para material con capacidad de flujo, granulado, grumoso y/o primero con capacidad de flujo y que después se endurece, en particular paredes perimetrales de canteros de suelo elevado o similares, - donde a dos de sus lados opuestos, paralelos uno con respecto a otro, respectivamente puede conectarse lateralmente al menos otro panel (30') diseñado del mismo modo, formando un borde vertical común (45) de
