Author(s)

G. Ren & Y. M. Xie

Abstract

Excavation in rock masses induces complex stress redistribution around the opening. Inter alia, the stability of the opening is principally dependent on the stresses around the opening. The most influential factor attributing to the stress distribution is the geometrical shape of the opening. As such, finding the optimal shape for an underground excavation has practical significance in increasing stability and lowering support costs. This paper describes an approach to the shape optimization of underground excavation using Evolutionary Structural Optimization (ESO) techniques. Through illustrated examples, it is demonstrated that ESO method can be used to explore the excavation shapes that give optimized performance in terms of stress distribution and stability. The method is validated and compared with theoretical solutions. An example of a three dimensional case is presented in comparison with a well-known application case. Keywords: excavation, cavern, finite element, optimization, evolutionary structural optimization, numerical analysis. 1 Introduction Stability is one of the primary considerations in an underground excavation design in rock masses. The stability of a rock structure is usually dependant on a number of factors, including the rock mass strength, supporting system and the shape of the excavation. In underground rock structure construction, the rock is used as a structural material which is subjected to massive stress regime change due to exaction. The shape of the excavation influences the stress distribution around the excavation, which in turn affects the stability of the excavation. In addition to satisfying the intended functional requirements of the excavation, it is important to select a propitiate excavation shape that gives the maximum

Keywords

excavation, cavern, finite element, optimization, evolutionary structural optimization, numerical analysis.