A decision approach on risk-control scheme recognition for karst excavation engineering

Abstract

Risk events can be frequently encountered in karst geological environments during excavation construction; thus, a suitable risk-control scheme is essential to reduce the negative impact of accidents. A decision-making approach based on the fuzzy VIKOR method is proposed to identify the optimal risk-control scheme, where a triangular fuzzy set is adopted to express the experts’ judgements. A decision hierarchy is constructed based on four criteria and 12 sub-criteria, which are determined based on engineering experience and the construction environment. The developed approach was utilized to determine the optimal risk-control scheme to address risk events for excavation construction in karst regions. A countermeasure scheme, that is, pressure grouting with a two-phase liquid system, was implemented. The basic principles and steps of the implementation of the proposed scheme are presented. The applicability of the identified scheme was verified by the core recovery and modified number of blows using a standard penetration test. A flowchart of optimal scheme identification for geotechnical engineering practice is provided.