Underground excavation shape optimization using an evolutionary procedure

Underground excavation in either soil or rock induces complex stress redistribution around the opening principally depending on excavation geometry, in situ stresses and material properties. Finding the optimal shape for an excavation based on stress distribution has practical significance in increasing stability and lowering support costs. This paper presents a new approach to the optimization of underground excavation shapes using an evolutionary structural optimization (ESO) procedure. Illustrated examples show that the ESO method is applicable to the optimization of underground excavation shapes. Both two- and three-dimensional cases are considered and compared with theoretical solutions. Optimal shapes of underground excavations under different virgin stress states are also presented.