12.2 General Procedure of Back Analysis in Excav⁃ation Issues
The procedures of back analysis can be generally illustrated as Figure 12.2.The mathematical procedure of optimization consists essentially of 2 parts：（1）the formulation of an error function measuring the difference between model responses（or analytical responses）and experimental results and（2）the selection of an optimization strategy to enable the search for the minimum of this error function.
Figure 12.2 A common scheme of back analysis
