搅拌桩内套打钻孔灌注桩在暗浜深基坑围护工程中的应用

Application of mixing piles in the set of bored piles in hidden creek fills foundation

在暗浜地层内施工钻孔灌注桩时,易产生钻孔扩径、孔内塌方事故,产生"叉腿桩"及诱发搅拌桩次生"叉腿",造成钻孔灌注桩与搅拌桩之间的产生大的缝隙。基坑开挖时,基坑外侧的地下水沿缝隙渗入,造成基坑外侧土体压缩变形,引起地表开裂、产生不均匀沉降。搅拌桩内套打钻孔灌注桩系先用低渗入量水泥将暗浜土搅拌成复合土,提高暗浜土的质量,然后在复合土内钻进成桩,其作用是避免钻孔灌注桩在暗浜土段的扩径、塌方超灌事故,确保了基坑桩基围护工程施工质量。

The construction of bored piles in the hidden creek formation, it goes easy generation drilling hole diameter and hole collapse accident, ＂ fork leg pile＂ and mixing pile induced secondary fork leg, and mixing piles and bored piles has big gap. In the excavation of foun- dation pit and foundation pit , lateral groundwater goes along the aperture infiltration, cau- ses soil foundation pit lateral compression deformation, surface cracking, and uneven settle- ment. Mixing piles within a set of bored piles is first with a low infiltration amount will be hidden creek soil cement mixing composite soil, to improve the quality of the hidden creek soil, and then within the composite soil drilling pile, its role is to avoid the hidden creek soil section of bored piles in hole enlargement, super collapse accidents, to ensure the quality of the project.