Effect Analysis of Different Treatment Methods for Soft Soil Foundation of Highway

With the rapid development of Guangdong, Hong Kong and Macao Bay area, the intercity rapid traffic network with high-grade highway as the main part has been developed rapidly. At the same time, the technology related to the soft soil foundation treatment of highway has also been developed. Based on a highway project in Foshan, Guangdong, this research used on-situ monitoring to study 4 kinds of soft soil foundation treatment methods, including preloading method, cement mixing pile, high-pressure jet grouting pile and Cement Flying-ash Gravel (CFG) pile, and then comparatively analyzed the influence of different treatment methods on the settlement of soft foundation. Finally, hyperbolic method was used to calculate the final settlement and post-construction settlement. The results showed that under the similar thickness of soft soil layer, treatment depth and filling height, CFG pile and high-pressure jet grouting pile have the best effect of controlling settlement after construction, which are 8.638mm and 14.584mm respectively; Cement mixing pile was followed by 23.196mm; preloading method are the worst at 71.731mm. In addition, the cumulative settlement of the preloading method is the largest, which are 212mm; the cement mixing pile is the second, which are 160mm; the CFG pile and the high-pressure jet grouting pile are the smallest, which are 120mm and 132mm, respectively. The research results provide a basis for the design and construction of soft soil foundation treatment for highway in the future.

Keywords: Treatment effect of highway soft soil foundation; Bagged sand well; Cement mixing pile; High- pressure jet grouting pile; CFG pile