Construction method of precast pile in thick-slag-stone-layer field

The invention relates to the technical field of the industrial and civil buildings, in particular to a construction method of precast pile in thick-slag-stone-layer field. The method comprises steps of: (1) digging and removing all slag above the reference height of the bottom of a pile cap; (2) when the thickness of the slag layer is not more than 5m, for situations of single pole and two poles, punching to the raw soil layer under the slag stone layer and then backfilling, for situations of three piles or more, digging and removing all remaining slag stones under a pile cap, removing the slag stones with large grain sizes, mixing the remained slag stones with small grain sizes with clay and backfilling the pit; when the thickness of the slag layer is more than 5m, digging and removing 2-3m remained slag under the pile cap, removing the slag stones with large grain sizes, mixing the remained slag stones with small grain sizes with clay and backfilling the pit; punching to the raw soil layer under the slag st