( 3 ) rock bolts are used as an extension of the supporting piles . this structure solves the embedding problem of cantilever pile and is newly applied in foundation trench in china . no environment contamination appears in this old crowed town because no detonation or mechanical drilling ( 3 )利用岩石锚杆作为围护桩的延伸成功地处理悬臂桩嵌固的问题,该结构方式的应用为国内首例,避免了在旧城镇老房屋密集区基岩爆破和机械成孔对周围环境的影响和污染。