铁路工程技术与经济

针对硬质砂岩地质条件下水中围堰施工的技术难题，本文提出了一种创新的锁扣式钢管桩围堰施工工法。在硬岩地层中，传统围堰管桩难以直接打设，且引孔过程中砂层漏砂、钻渣泄漏导致成孔困难，爆破施工更对邻近铁路运营安全构成威胁。本工法采用预引孔技术结合特制防漏渣钢护筒，通过分批次成孔与回填工艺，有效解决了成孔质量与地层稳定性问题。锁扣式钢管桩可实现工厂化预制，现场通过逐根插打工艺快速成型，较传统双壁钢围堰减少大型机械投入，缩短施工周期达30%以上。有限元模拟与工程实践表明，该方法在结构稳定性、施工安全性和经济性方面具有显著优势，且对周边环境影响可控，为复杂地质条件下的水中围堰施工提供了可靠的技术路径。

To solve the technical problems of underwater cofferdam construction in hard sandstone geological conditions, this paper puts forward an innovative construction method of lock-type steel pipe pile cofferdam. In hard rock layer, it is difficult to directly set up traditional cofferdam pipe piles, and it is difficult to form holes due to sand leakage and drilling slag leakage in the process of guide-hole introduction. Blasting construction poses a threat to the operation safety of adjacent railways. In this method, the guide-hole introduction technology combined with special slag-proof steel casing is adopted, and the problems of hole-forming quality and formation stability are effectively solved by batch hole-forming and back-filling technology. Lock-type steel pipe piles can be prefabricated in factories, and can be rapidly formed on site by inserting and punching one by one. Compared with traditional double-wall steel cofferdams, large-scale mechanical investment is reduced, and the construction period is shortened by more than 30%. Finite element simulation and engineering practice show that this method has obvious advantages in structural stability, construction safety and economy, and can control the impact on the surrounding environment, which provides a reliable technical path for underwater cofferdam construction under complex geological conditions.