Simplified Simulation Method and Practical Prediction Tool for Mechanized Tunnelling Induced Settlements Based on Hybrid Volume Loss‐Grouting Pressure Method

ABSTRACT Settlement prediction is crucial in the design and construction of mechanized tunnels, with numerical simulation serving as an effective tool for estimating settlement trough. This study proposes a simplified two‐dimensional simulation method as an alternative to complex and time‐consuming three‐dimensional simulations for predicting settlement trough. By integrating the volume loss method and grouting pressure method, this study introduces a hybrid volume loss‐grouting pressure (VL‐GP) method, a two‐dimensional simplified simulation approach for estimating settlement in single and twin mechanized tunnels. The proposed method was validated using six historical cases, demonstrating its advantages over other simplified simulation methods in accurately reflecting the construction process and improving prediction accuracy. A parameter study on the hybrid VL‐GP method examined the influence of soil properties, tunnel geometry, and construction parameters on settlement troughs in mechanized tunnels. Results indicate that clay exhibits greater sensitivity than sand, emphasizing the need to consider multiple factors when using settlement control as a design and construction criterion. To facilitate the application of the hybrid VL‐GP method, a graphical user interface (GUI) was developed using FLAC3D and Gmsh, integrating Python and Fish programming to provide a user‐friendly tool for predicting and evaluating induced settlement in mechanized tunnels.