bank something up
(against something) 1. to heap or mound up something so that it presses against something. Walter banked the coals up against the side of the furnace. He banked up the coals against the side. Tim banked the coals up.
2. to heap or mound up something to guard against something. They had to build barriers to hide behind. They banked dirt and rubble up against the oncoming attackers. Who banked up this dirt against the flood? The river was rising, so we banked some dirt up.