Analysis of Causes of CFG Pile Necking in Saturated Soft Soil Layer and Its Control Measures

In recent years, composite foundation technology has been widely used in foundation treatment. Composite foundation theory has become an important research topic in the field of geotechnical engineering. CFG pile (Abbreviation of cement, fly ash, and gravel pile) in composite foundation is one of the commonly used technologies. It has advantages such as simple construction, reliable quality and low cost. When it is used in soft foundation treatment, it significantly improves the bearing capacity, reduces settlement, and turns waste (fly ash) to treasure, which benefits economic and social significantly. During construction, various defects in construction quality will affect the effect of soft foundation treatment. CFG pile necking is one of the more representative quality defects. This paper combined some project examples to analyze the causes of CFG pile necking and develop effective control measures for it which has a certain reference value towards the quality control of the technolog