两次成桩法在高承压水地层中的应用研究  

Application of Twice Piling Method in High Pressure Fractured Water Layer

作　　者：杨宗维 YANG Zongwei(Shenzhen Tunnel Engineering Co.,Ltd.Shenzhen 518034,China)

机构地区：[1]深圳市隧道工程有限公司,深圳518034

出　　处：《广东土木与建筑》2024年第1期29-32,共4页Guangdong Architecture Civil Engineering

摘　　要：为解决在高承压裂隙水地层施工旋挖钻孔灌注桩时遇到的涌水、塌孔、缩颈等技术难题。经试验研究,创新提出两次成桩法,即初次扩径成桩结合二次按设计尺寸成桩。成功解决上述工程难题。工程实践表明,两次成桩法在不需要特殊桩基设备的条件下,可实现在高承压裂隙水地层快速高效高质量成桩施工。初次扩径成桩采用C20号混凝土,混凝土浇筑1 d后,强度大于5 MPa小于10 MPa时进行二次成桩,施工工效最高且成桩质量优异。与传统的平衡水头法相比,两次成桩法既可节约工程直接成本,又可缩短工期,经济效益显著,且避免了机械高台作业带来的安全风险,提高施工安全性。为该类地层条件下的钻孔灌注桩快速成桩施工提供了技术借鉴。A two-stage pile forming method was innovatively proposed after many times experimental research to solve technical problems such as water gushing,hole collapse,and necking encountered during the construction of rotary drilling cast-in-place piles in high pressure fractured water layers.The slurry and solid formed by the infiltration of concrete slurry into the surrounding soil combined with the expansion part form a double protective wall while suppressing the pressure head,ensuring the quality of the pile and successfully solving the above engineering problems.The results indicate that the two-stage pile forming method can achieve fast,efficient,and high-quality pile forming construction in high pressure fractured water formations without the need for special pile foundation equipment.The initial expansion pile is made of C20 concrete.After pouring the concrete for 1 day,the secondary pile is formed when the strength is greater than 5 MPa but less than 10 MPa.The construction efficiency is the highest and the pile quality is excellent.Compared with the traditional balanced head method,the two-stage pile forming method can not only save direct engineering costs but also shorten the construction period,with significant economic benefits.It also avoids safety risks caused by mechanical on the high platform operations and improves construction safety.This method could provide a technical reference for the rapid construction of bored piles under such geological conditions.

关 键 词：钻孔灌注桩 高承压裂隙水 两次成桩 双重护壁 快速高效 

分 类 号：TU473[建筑科学—结构工程]