Tunnel Design and Sensitivity Analysis

Sensitivity analysis should be employed to examine the effect of the variability of selected parameters on critical response of a construction, using credible upper and lower bounds. This investigation performs such an analysis for an actual tunnel design case by means of numerical modeling. A local method, which is a partial derivative of the output with respect to several input factors, is used so as to ensure ease of use for the designer. In this way, the effect of varying geotechnical parameters over their possible values with respect to internal forces and displacements of the tunnel temporary lining is evaluated. The analysis includes not only assessment of the greatest influence on the item under observation by use of new types of diagrams that provide better comprehension but also a first order reliability evaluation on the effect of input parameters with respect to the reinforcement requirements of the temporary lining.