On the basis of the first proposed soil layer composite ratio, a single comprehensive index calculation model of geological characteristics in the Caoqiao Tunnel, China, is established using AHP (Analytic Hierarchy Process) and WAM (weighted average method). A model of geological characteristics is then used to discriminate a number of geologically characteristic groups. The results show that the curve of key driving parameters of the earth pressure balanced (EPB) shield corresponds well with the curve of geological characteristics. Additionally, the optimization measures for the driving parameters under different geological conditions are put forward based on a correlation coefficient matrix. This research serves as a guide for future investigations into construction optimization of large-diameter EPB shields used in tunneling.