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

Abstract

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. The modified solution proposed in this study has significant practical application value in deep-buried weak tunnel engineering, particularly in industries facing complex geological conditions, such as underground mining and transportation tunnel construction. By considering the self-weight of the surrounding rock, the derived pure elastic stress solution and approximate plastic zone solution enable more-accurate analyses of tunnel excavation, providing a reliable foundation for engineering design. Furthermore, the research findings provide valuable theoretical support for ensuring the safety and economic viability of deep-buried soft rock tunnels, facilitating the successful implementation of related engineering projects. Ultimately, this research enhances the understanding of tunnel behavior under challenging conditions, promoting safer and more efficient engineering practices.