铁路海相软基CFG桩加固试验研究

Experimental Study on Marine Soft Ground Improvement by CFG Pile in Railway

针对CFG桩复合地基加固海相软土的适用性问题,在铁路正线进行了应用试验。采用CPTU孔压静力触探原位测试方法确定地基土状态指标、强度和变形指标;分别对CFG桩施工过程中的桩土扰动和成桩质量,路基填筑期及静置期CFG桩复合地基的桩土应力分布、孔隙水压力变化、沉降和变形进行了现场监测分析。结果表明:CPTU可以为软基加固处理提供更多的地基土参数;CFG桩复合地基适用于苏北地区海相深厚软土加固;CFG桩复合地基方案对加快地基沉降收敛和减小地基的沉降量效果显著,丰富了海相深厚软土复合地基处理技术与工程实践。

In order to identify the suitability of composite foundation reinforced by CFG pile for marine deep soft ground improvement, the experimental study was carried out in main line railway. CPTU was adopted to confirm state index, strength index and deformation index; field monitoring and analysis were carried out to obtain and evaluate disturbance state of soil surrounding piles, pile quality, load distribution, excess pore water pressure, settlement and deformation during the period of CFG pile construction, embankment construction and standing. The results demonstrate that more clay indexes can be provided by CPTU for soft ground improvement; CFG pile composite foundation is suitable for marine deep soft ground improvement in northern Jiangsu area; marine deep soft subgrade reinforced by CFG pile can significantly reduce embankment settlement and accelerate convergence displacement. Furthermore, foundation treatment technique and engineering practice for marine deep soft ground composite foundation reinforcement have been enriched by this experimental study.