A case method approach for interactive risk analysis of tunnel 'design-for-constructability' concept.

摘要

This thesis introduces approaches dealing with the inherent in rock engineering uncertainty. Uncertainty arises from our inability to form a complete structure of the rock mass before construction, during the design stage of a project, as well as our inability to comprehend fully interactions between rock mass and excavation domains.; By combining prior knowledge, related to a frequency function that geologic parameters affecting construction in rock are likely to follow, with experts' valuations, a range of possible rock mass conditions to be anticipated during construction is generated. This is used to establish the reliability of a design solution as well as the risk associated with a bidding price. Therefore, a comparison is possible between alternative designs on the basis of reliability and cost of a design solution.; Procedures are provided for incorporating the generated range of rock mass conditions with approaches to rock engineering design using simulation, and the Point Estimate Method. The decision tree method assists in deciding on the extent of an exploration program using the minimum expected opportunity cost as the selection criterion of an exploration-method of excavation. To depict uncertainty in tunnel construction, cost and time per excavated tunneling meter were correlated with the Rock Mass Rating index.; Using the Systems Design Methodology (SDM) for rock engineering enhanced by the elements of this work, a system of three objectives and their associated design components was defined that could have prevented a dispute between the owner and the contractor for Hex River Railroad Tunnel in South Africa. The development of the case study in the format of the SDM provided a method for case analysis, setting a framework for possible case study guidelines in rock engineering.; To identify interactions in rock tunneling a specific cause-and-effect matrix for rock tunneling was composed from information in literature. A dynamic representation of this matrix was investigated in respect to its potential for providing an index for predicting the "excavability" of rock mass conditions, using fuzzy cognitive maps.; A computer representation of the knowledge gained from this work is also part of this thesis.