泵吸反循环钻孔扩底桩施工技术

在同地质条件下,钻孔扩底灌注桩比同直径的钻孔灌注桩可提高承载力2～4倍;在同样的承载力要求下,扩底的钻孔灌注桩桩径较小,可节省大量混凝土和钢筋.钻孔扩底灌注桩具有承载力高、减少投资、缩短工期等特点,适用于大跨度的公共建筑.广深港铁路客运专线深圳北站桩基工程采用带扩大头的钻孔灌注桩和扩底后压浆施工工艺,效果良好.

CONSTRUCTION TECHNIQUE OF PUMPING REVERSE CIRCULATION BASE-ENLARGED BORED PILE

Under the same geological conditions, base-enlarged bored filling pile, compared with the bored filling pile with the same diameter, can improve 2 to 4 times the bearing capacity; with the same requirement for bearing capacity, the base-enlarged bored filling pile has smaller diameter and can save a great amount of concrete and steel bar. Base-enlarged bored filling pile has many characteristics, such as high bearing capacity, small investment and short construction period, etc., and it is applicable to wide-span public buildings. Bored filling pile with enlarged end and base-enlarging grouting construction technique are adopted in the pile foundation project of Shenzhen North Station of Guangzhou-Shenzhen-Hong Kong Express Rail Link, and favorable effects are obtained.