跌跌撞撞 is an AABB reduplicated form. 跌 means 'to fall' and 撞 means 'to bump'. The AABB reduplication vividly describes the manner - lurching from trip to bump repeatedly. It functions as an adverb before 地.
usage
Can be used literally (drunk or injured walking) or figuratively (a business stumbling through difficulties, e.g. 公司跌跌撞撞走到了今天).