海洋环境大直径桩基“超重锤+低液面”施工技术

Construction Technology of "Overweight Hammer + Low-liquid Level" of Large-diameter Pile Foundation in Marine Environment

摘要:

针对复杂海况中大直径钻孔灌注桩施工常见问题，以某工程项目为例，基于项目地质情况，对大直径变径钻孔桩施工在设备选型、工艺优化、成品质量控制等多方面进行详细研究,对比分析了不同施工工艺下的成桩质量与施工工效等，实践表明：“低液面（较原来水头标高降低4~5 m）+超重锤（直径d=2.5 m，重14 t）”组合施工工艺冲击成孔工艺在高强裸岩工况下施工，相较于传统工艺，可有效解决了复杂海洋环境坚硬地层中桩基成孔过程中漏浆、串孔等诸多工程难题，Ⅰ类桩成桩率达到99%以上，同时本文对桩基成孔过程中的施工重难点及质量控制要点进行详细说明，为类工况桩基施工提供可借鉴解决方案。

Abstract:

In view of the common problems in the construction of large-diameter bored pile in complex sea conditions, taking an engineering project as an example, based on the geological conditions of the project, the construction of large-diameter reducing bored pile is studied in detail in terms of equipment selection, process optimization final product quality control and other aspects. The final pile quality and the construction efficiency are compared and analyzed under the different construction technologies. The practice shows that under the condition of high strength bare rock, the combined construction process of "low liquid level (lower than the original water head elevation of 4~5 m) + heavy weight hammer (diameter d=2.5 m, weight 14 t)" is used to impact holes. Compared with the traditional process, it can effectively solve many engineering problems such as slurry leakage and holing string during pile foundation formation in hard strata in complex marine environment. The pile formation rate of Class I piles is more than 99%, and the construction difficulties and quality control points in the process of pile foundation holing are detailed, which provides a reference solution for the construction of similar pile foundation.