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Rockfall analysis traditionally has used conventional stationery tools, that is, pencil and paper, for data collection. Traditional methodologies are being revisited with the advent of personal digital assistants (PDAs) or pen-based computers that enable field data to be collected electronically. The advantages over data collection with pencil and paper include automatic error and data integrity checks during data input and the elimination of manual data entry. PDAs also allow automatic branching to solicit data input on the basis of previous data entered and support for code or scripting, which can be used to create unique files names from the data entered. These advantages are illustrated in an electronic data collection methodology as implemented within a rockfall hazard rating system for the Tennessee Department of Transportation.

Rockfall analysis traditionally has used conventional stationery tools, that is, pencil and paper, for data collection. Traditional methodologies are being revisited with the advent of personal digital assistants (PDAs) or pen-based computers that enable field data to be collected electronically. The advantages over data collection with pencil and paper include automatic error and data integrity checks during data input and the elimination of manual data entry. PDAs also allow automatic branching to solicit data input on the basis of previous data entered and support for code or scripting, which can be used to create unique files names from the data entered. These advantages are illustrated in an electronic data collection methodology as implemented within a rockfall hazard rating system for the Tennessee Department of Transportation.

Fractures, joints, and other discontinuities significantly influence the stability of excavations in rock. Unstable blocks of rock in the roofs of tunnels can have a significant effect on the safety and economic feasibility of highways and railroads. The stability of tunnel roof keyblocks subject to self-weight and surface forces is examined using linear programming methods. An instability measure based on the concept of fuzzy sets is used to characterize the level of instability. On the basis of analysis of the instability measure, the support pressure required to stabilize the tunnel roof can be estimated. A probabilistic analysis based on the expectation of the instability measure is used to examine the effect of the uncertainties caused by the variability of rock material properties.

Fractures, joints, and other discontinuities significantly influence the stability of excavations in rock. Unstable blocks of rock in the roofs of tunnels can have a significant effect on the safety and economic feasibility of highways and railroads. The stability of tunnel roof keyblocks subject to self-weight and surface forces is examined using linear programming methods. An instability measure based on the concept of fuzzy sets is used to characterize the level of instability. On the basis of analysis of the instability measure, the support pressure required to stabilize the tunnel roof can be estimated. A probabilistic analysis based on the expectation of the instability measure is used to examine the effect of the uncertainties caused by the variability of rock material properties.