The optimized calculation method for spacing and cross section of underground tunnels

Both spacing and cross section of tunnel are two important problems in design of a project and they are correlative. The unified design variables have been used to indicate the characteric sizes of spacing and cross sections of tunnels. The total area of failure zone within surrounding rock has been set as objective function. Whereas the constraint conditions are fixed in accordance with operation requirements. This kind of non linear optimization problem with constraint has been solved in a practical project. The results are reasonable.