The random wedge usually occurs in the deep excavation of side slope of hydraulic structures. According to the three-dimensional network computer simulation

A numerical model of probability statistics for distribution of rockmass is established. A computational program for the method has been accomplished. With the program all polygons in trace figure are sought; and all the potential rocks can be found out of all the finite rock blocks which have free faces exposed by area-judgment method. The method is proved to be reasonable from simulated results of real engineering.