Determination of settlement trough width and optimization of soil behavior parameters based on the design of experiment method (DOE)

The expansion of the settlement trough is an important factor in the risk assessment of the tunneling induced settlement. The increase of settlement trough requires buildings to be included in the impact zone, which causes damages. This paper conducts estimation of the settlement trough width (STW) using empirical approaches, field measurement data and numerical solutions. The credibility of the numerical results is affected by accuracy of the input data such as geotechnical parameters (E, c, and φ). Therefore, an approach in which 3D finite element modeling (FEM) and a Taguchi’s experimental design are combined to estimate the geotechnical parameters (E, c, and φ), is used. The field settlement measurements are used to validate the numerical modeling results. The results indicate that Taguchi’s (DOE) method is an effective approach to estimate the geotechnical parameters. In addition, numerical modeling provides a wider settlement trough than the empirical methods and instrumentation data. However, maximum settlement in numerical modeling has the minimum deviation of the filed settlement data. There is a good agreement between empirical approaches and field settlement data to estimate i-value and STW parameter. The results of numerical simulation overestimated the settlement trough width, which causes more buildings to be included in the tunnel impact zone. It demands more extensive study to assess the tunneling induced building damage, which is more conservative.