无靴端夯扩灌注桩工法.doc

无靴端夯扩灌注桩（简称夯扩桩）是一种采用锤击方式将桩端现浇混凝土夯扩成大头形的灌注桩，由浙江省机械施工公司与杭州市城建设计院等单位于1979年共同研试成功，它与国外已获专利的“法兰克桩”和“阿尔法桩”同属桩端夯扩型灌注桩。该类桩除具有技术可靠、工艺科学、施工周期短、无泥浆和工程造价低等优点外，对同直径的灌注桩而言，单桩承载力有较大幅度提高。

1特点
    1.l由于桩端通过夯扩形成大头，且可根据不同设计要求进行多次夯扩或多节夯扩，增大了桩端或桩身局部截面积，提高了单桩垂直承载力（RK）。
    1.2采用同桩身同标号的干混凝土作土塞，成功地解决了施工中孔底止淤的关键质量问题，减少了桩的沉降，同时拨管成桩时，桩身混凝土是利用柴油锤和内夯管的自重压密成形，保证了桩身质量。
    1.3由于夯扩桩是采用打入并夯扩成桩，故对桩周及桩端地基土有明显挤密作用，从而提高了地基土强度，对地基处理有一定复合作用，同时对防止砂土地震液化有一定效果。
    1.4对设计要求的适应性强，可根据地基土的分布条件与性质来选择桩长和调整夯扩参数，以满足设计所需的承载力。
    1.5夯扩桩施工简便，周期短，施工中不存在泥浆处理等问题，降低工程造价，具有明显的经济效益。
No boots side rammer piles (referred to as compaction pile) is a way by hammering situ concrete pile rammed into a bulk form of the pile, by the mechanical construction company in Zhejiang Province and Hangzhou Urban Construction Design Institute in joint research and testing in 1979 success, it has been patented abroad, "Frank piles" and "Alpha pile" belong to the same type pile rammed pile. In addition to a technical reliability of such piles, process science, short construction period, no mud and engineering and low cost advantages, in terms of the same diameter piles, pile capacity has improved substantially.

1 Features
    1.l as pile rammed through the formation of the bulk, and can be repeated for different design requirements or section rammed rammed, increases the pile or pile partial cross-sectional area, increases the vertical bearing capacity of single pile (RK ).
    1.2 using the same pile with the label of the dry soil plug of concrete for the successful solution of the construction of the key hole quality of the end of silt, reducing the pile settlement, while allocating pipe pile, the pile of concrete and in the use of diesel hammer Undercutting the weight of secret self-forming, to ensure the pile quality.
    1.3 As the pile is the use of rammed and rammed into the pile, so on the pile and pile soil compaction significant role, thereby increasing soil strength, on the ground dealing with the role of a certain compound, at the same time to prevent the sand liquefaction have a certain effect.
    1.4 adaptable design requirements, the distribution according to soil conditions and the nature of selection and adjust long tamping expansion pile parameters, in order to meet the design requirements of the bearing capacity.
    1.5 Compaction Column Construction is simple, short period, the construction does not exist in the mud disposal problems, reduce the project cost, with obvious economic benefits.