expression, godan verb (-ku)
pile up a mound; build a tumulus
Literally means to heap up earth to form a mound or tumulus. Often used in historical or archaeological contexts.
古代の人々は、王の墓として巨大な塚を築いた。
Ancient people built huge mounds as tombs for their kings.
Compound of 塚 (mound) + を (object marker) + 築く (to build, pile up). The expression is straightforward and transparent.