Modified extension evaluation of foundation pit engineering combined with orthogonal experiments and multiple linear regression

In recent years, excavation work of underground railways has been becoming increasingly complex in the congested urban areas and frequently exposed to substantial hazards. For this reason, it is important in the early stages of project planning to determine the foundation pit engineering grade (FPEG), so that suitable measures can be put forward and implemented before the risks really occur. The extension evaluation is modified by taking multiple linear regression according to the FEM analysis together with orthogonal experiments. The resulting model can be used to ensure the FPEG and comprehensively reflect the influences of the three factors on the grade. Six illustrative cases have been applied into the proposed model to show its capabilities and the results are compared to those derived from the conventional manner. The modified extension evaluation (MEE) method solves the human-related subjectivity problem of the conventional manner, which is capable of handling the quantitative and objective information.