Modified Analytical Solutions for Purely Elastic Stress and Approximation of the Plastic Zone in Deep-Buried Circular Roadways

Traditional deep-buried tunnel excavation theories often overlook the self-weight of surrounding rock within the calculation zone, leading to increased design errors and potential safety risks. This study proposes an analytical theoretical model for tunnel excavation under non-hydrostatic stress conditions that considers the self-weight of surrounding rock. A pure elastic stress solution and an approximate solution of the plastic zone are derived using elastoplastic mechanics. The results demonstrated a high correlation between the derived solutions and numerical simulation results. Sensitivity analysis and the method of controlling variables revealed key influencing factors of the pure elastic stress solution and approximate plastic zone solution. The findings of this research significantly enhance the accuracy of analytical tunnel excavation theories and provide crucial theoretical support for stability analyses of surrounding rock in related engineering applications.