Adaptability Evaluation of Rotary Jet Grouting Pile Composite Foundation for Shallow Buried Collapsible Loess Tunnel

The deformation control effect of loess tunnel composite foundation plays an important role in optimization design and reinforcement effect evaluation. Systematically evaluate the adaptability of the composite foundation of jet grouting pile in shallow collapsible loess tunnel. Taking the shallow buried section of Fujiyao Tunnel with a buried depth of 20 m as an example, using MIDAS finite element numerical simulation software, the foundation deformation control during construction and settlement control after construction are systematically studied, the differential deformation control is analyzed, and the reinforcement effect of the tunnel bottom is evaluated. The results show that the uplift displacement can be controlled by changing the pile length and increasing the replacement ratio. The combination of long and short piles can significantly reduce the uneven settlement and plastic zone of the foundation. The uneven settlement of 9 mm can be used as the evaluation index of the composite foundation reinforcement effect in a shallow buried section of the loess tunnel.

Automated summary

This study systematically evaluates the adaptability of jet grouting pile composite foundation in shallow collapsible loess tunnel, using MIDAS finite element numerical simulation software. The control of foundation deformation during construction and settlement after construction is studied, and the differential deformation control is analyzed. The results show that the uplift displacement can be controlled by adjusting the pile length and replacement ratio, and the combination of long and short piles can reduce uneven settlement and plastic zone of the foundation. An uneven settlement of 9 mm can be used as an evaluation index for the reinforcement effect of the composite foundation in a shallow buried section of the loess tunnel.