Rectangle piles have been widely used to stabilise problematic slopes with typically non-linear plastic deformation behaviour. This paper introduces analytic solutions to soil arching effect based on the slope soil and piles interaction. In view of stress condition of the passive piles subjected to the lateral force, the stress expression of arbitrary point of the soil behind the piles is derived from soil mechanics, elastic and plastic theories, and the mechanical model of soil arch is built. Stress isoline distribution of soil arch is found to be hyperbolic, shoulder expansion arch, saddle and domal. After the influence factors on soil arching effect are discussed in detail, the governing equation of maximum pile spacing is established based on the Mohr-Coulomb theory of soil shearing strength. Finally, a practical case of slope prevention engineering is given for the design of pile spacing to verify the rationality of analytic solution.

Winkler elastic foundation beam theory is often used to observe the influence of underground engineering construction on pipelines. Excavation under existing pipelines disturbs the lower strata to varying extent, which creates significant differences in the subgrade coefficients. Ignoring these differences can severely impact the accuracy of calculation results. A theoretical model of the effects of underground excavation on upper-level existing pipelines was developed in this study based on Winkler elastic foundation beam theory and considering the difference of subgrade coefficients under the existing pipeline. Methods for determining the subgrade coefficient under the influence of construction disturbance and other relevant parameters are proposed. The theoretical model can be used to calculate the settlement of an existing pipeline under the influence of underground excavation. The calculated settlement was compared with settlement measurements to find that the subgrade coefficient of the excavation section is the most important parameter in the calculation process. The suitable value range of the excavation subgrade coefficient is relatively large, as it has a relatively minor influence on the calculation result. When the value of subgrade coefficient of each section is appropriate, the calculated settlement curve is in close accordance with the measured settlement curve.