夯扩桩,顾名思义,是一种以桩端扩大头支承为主,桩身摩擦力为辅的扩底桩与沉管灌注桩合一的桩型。夯扩头的形成,是将双管打到设计标高,拔出内管,往外管内灌入一定高空的扩底混凝土,内管插入,将外管拔起一定高度,然后用静压或施加锤击力,通过内夯管传给桩端混凝土,迫使混凝土向下和向四周基土挤压形成扩大头,这样既增大了桩端截面积,又改善了地基土密实度,从而使桩的承载力有较大幅度提高。而 The ram-expanded pile, as its name implies, is a type of pile that combines the dia prestressed pile and the immersed cast-in-place pile, which is mainly supported by the enlarged head of pile head and supplemented by the friction force of the pile body. The expansion head is formed by driving the double pipe to the design elevation, pulling out the inner pipe, and pouring a certain amount of high-rise concrete into the outer pipe. The inner pipe is inserted, the outer pipe is pulled up by a certain height, and then the static pressure or hammer is applied. The impact force is transmitted to the concrete at the pile end through the internal malleable tube, forcing the concrete to expand downward and toward the surrounding soil to form an enlarged head. This increases the cross-sectional area of ​​the pile tip and improves the compaction of the foundation soil. The bearing capacity has been greatly improved. and