DEM study of the shear behavior at the nodular pile-cemented soil interface in static drill-rooted nodular pile

• A nodular pile-cemented soil numerical shear model was developed. • Evolution of nodular pile-cemented soil interface shear behavior was analyzed. • Effect of node angle and width of nodular pile were discussed. • A nonlinear mechanical behavior model for the nodular pile-cemented soil interface was proposed. The bearing capacity of static drill-rooted nodular piles (SDRN) can be significantly affected by the load transfer and failure modes at the nodular pile-cemented soil interface. This study conducted a series of three-dimensional nodular pile-cemented soil interface shear tests, and the corresponding numerical models were established using the continuum-discrete coupling method. The evolution of the shear behavior of the nodular pile-cemented soil interface was analyzed, and the effects of nodular pile node angle and width on the interface shear characteristics were investigated. The results indicate that the increase of the node angle not only reduces the interface bonding force, but also weakens the interlocking effect between the node and cemented soil. Increasing the node width within a certain range can significantly improve the interface shear resistance and deformation coordination by enhancing the mechanical interlocking effect and optimizing the stress transfer path. However, excessive increase of node width leads to intensified stress concentration within the cemented soil, resulting in a decrease in peak shear resistance. Finally, a nonlinear mechanical behavior model is proposed for the nodular pile-cemented soil interface. This study provides technical guidance for the design and application of SDRN piles in engineering.