扩孔取砂工艺助预应力管桩穿越密实砂层 : prestressed pipe pile meet in the process of pile driving a hard construction is very difficult sandwich, combining with engineering practice experience, the paper introduces a bit reaming take sand and sodium based bentonite pulp of the slurry-supported way to destroy a hard sandwich method. Enlarge hole take sand process is in the tube pile will reach sand layer, the r