苏联在第四纪粘土层上建筑的工业建筑和构筑物采用的摩擦钻孔桩,当桩通过较厚的软土层(16米以上)到达持力层时,由于孔底土被扰动,试验实测证明端承力很小。为了增加端承力,在饱和土中采用粘土水泥浆处理,在含水量低的持力层中采用预压的办法,使土密实。有两种压密上的方法:一种是往孔底填砾石;另一种是打入钢筋混凝土预制 Friction-drilled piles used in industrial buildings and structures constructed by the Soviet Union on the Quaternary clay layer, when the pile passes through a thick soft soil layer (above 16 meters) reaches the bearing layer, the soil in the hole bottom is disturbed. End bearing force is small. In order to increase the end bearing capacity, a clay cement slurry is used in the saturated soil, and the soil is compacted by adopting the pre-pressing method in the bearing layer with low water content. There are two methods of compaction: one is to fill the gravel to the bottom of the hole; the other is to break into the reinforced concrete prefabricated