Ground displacement modelling for sequential pipe-jacking in clayey strata

In densely built urban areas, the ground response to pipe-jacking is a critical concern. This study presents a mechanistically based analytical model for predicting ground displacements induced by sequential pipe-jacking of non-identical microtunnels in homogeneous clayey strata. The model accounts for both vertical and horizontal soil movements, incorporating geometric parameters, volume loss, and the influence of prior tunnel excavations through a disturbance factor. Vertical displacements are represented using a modified Gaussian distribution, while horizontal displacements are derived from vector orientation analysis and a depth-dependent empirical function. Validation was conducted through comprehensive comparisons with three-dimensional finite element simulations, published field monitoring data from pipe-jacking and shield tunneling projects, and existing analytical solutions. The model demonstrated strong agreement with these datasets, accurately capturing settlement magnitudes and trough evolution across multiple construction phases. Results indicate that tunnel diameter governs the maximum settlement response, while spacing and burial depth influence the spatial extent of deformation. The proposed model provides an efficient and reliable tool for preliminary ground movement prediction in sequential microtunneling, supporting risk-informed design and mitigation strategies in urban underground construction.