Abstract:The big-dianieter multi-pile foundations were applied by the Damingmen Bridge and the transverse bridge at Hengbin Port in Japan. The structures of the bridge foundations and its construction methods are described in this paper,and a rather new scheme for enlarg?ing the bore is proposed. The method described in this paper has better suitability,especially has certain reference value for constructing bridges under the difficult conditions, such as with weak ground,etc.