Effect of Double-line Parallel Shield Excavation on Adjacent Underground Pipelines

Abstract

Using a formula for the total settlement of deep soil and the Winkler foundation model, the force model for underground pipelines is simplified to obtain the ultimate bending moments and to calculate the stress and strain due to double parallel shield tunneling construction. The effects of soil conditions, tunnel horizontal spacing L, pipeline material, pipeline depth h and soil loss ratioηl/ηf on the force on an underground pipeline are investigated. The results show that changing the soil conditions and value of L can have a significant effect on the shape and magnitude of the pipeline’s ultimate moment curve, although changing the value of h has less of an effect. It is found that the larger the bending stiffness of the pipeline, the larger the distribution range of the ultimate bending moment and its peak value, but there is less of an effect on the shape of the curve. Changes in the ratioηl/ηf have some influence on both the shape of the curve and the values of the bending stiffness of the pipeline.

Keywords

• Double-line parallel shield
• Underground pipelines
• Ultimate moment
• Soil settlement