CFG桩-网复合结构软基加固技术及其实际应用

研究目的:探讨有关CFG桩加固软土地基的设计、施工等方面的问题。研究方法:通过CFG桩-网复合结构加固上海某高速铁路试验段深厚软土地基的工程实例,对该法处理软土地基的设计方法、施工工艺、质量检验方法及注意事项进行了详细的阐述,并对其加固软基机理进行了较为深入的分析和探讨,对两种不同桩长的加固效果、在路堤荷载下的沉降变形规律、土工格栅的应力应变等进行了相关试验和现场测试研究。研究结果:桩长为27 m穿透软土层的CFG桩-网复合结构,填筑施工完成8个月后能满足高速铁路(有碴轨道)对软土路基承载力和工后沉降5 cm的要求,为应用CFG桩加固技术进行深厚软基处理的设计、施工与质量检验等提供了可靠的数据和参考依据,为我国在软土地区修建客运专线积累了宝贵的经验。

REINFORCEMENT TECHNIQUE FOR SUBGRADE IN SOFT SOIL ZONE BY COMPOSITE STRUCTURE OF CFG PILE-NET AND ITS APPLICATION

Research purpose: The exploration is made on issues of design and construction for reinforcing subgrade in soft soil zone by CFG pile. Research method: The design method, construction technique, quality check method and cautions are described in details for reinforcing subgrade in soft soil zone by adopting composite structure of CFG pile-net and the mechanism of reinforcing subgrade in soft soil zone is analysed and explored on the basis of an example of reinforcing subgrade in deep soft soil zone in trial section of one high-speed railway in Shanghai by adopting composite structure of CFG pile -net. The relative experiments and site test research are made on the reinforcement effect of two different pile lengths, the law of settlement deformation and geogrid stress under embankment load. Research result: The composite structure of CFG pile-net to penetrate soft soil bed with pile length of 27 m can meet the requirements of the capacity of subgrade in soft soil zone against high-speed railway(ballast track) and post-construction settlement of 5 cm after eight months of ending filling. This provides the reliadble data and reference basis for design, construction and quality check of reinforcing subgrade in deep soft soil zone and provides the experience of building passenger dedicated railway line in soft soil zone.