A Cost Comparison Between Empirical and Engineered Support and Reinforcement Designs for Tunnels in a Low Stress Environment

摘要

Mines, after becoming operational, often retain the same support and reinforcement designsrndeveloped in the feasibility study. These designs are conceived from limited drilling data and regionalrnexperience, thus having an empirical fl avour. Empirical designs are perceived to be conservative,rncatering for a variety of failure mechanisms, which are not always present in mine developmentrndrives.rnThis begs the question: If you were to invest in the necessary resources to obtain suffi cient datarnand complete the required analyses for the different development drives in the mine, to engineerrnsupport and reinforcement scheme with the capacity to match the demand of the rock mass, whatrnthe difference in cost when comparing an empirical design to an engineered design?rnTo answer this question, mine tunnels with different geometries and orientations, where detailedrnstructural data was available, were selected for a comparative design exercise. Material cost,rndevelopment cost, cycle time and professional fees for engineered and empirical designs werernestimated. The outcome is summarised in the following paper that discusses the process followedrnand the results of the design comparison.