ABSTRACT

Geologic uncertainty in underground construction often leads to design and construction conservatism and hence to inflated costs. This paper presents a general model for the probabilistic prediction of tunnel geology, as a basis for developing more effective tunnel design and construction decision support systems. The geologic conditions along the tunnel alignment are modeled by a set of geologic parameters (such as rock type, joint density, degree of weathering, etc.), each following a continuous-space, discrete-state Markov process. The state probabilities for each geologic parameter are initially based on general geologic information and are later updated to reflect the outcomes and reliability of the location-specific, non-deterministic observations provided by exploration programs. The resulting posterior geologic parameter profiles are aggregated into a single probabilistic ground class profile that can be used for determining optimal tunnel design and construction strategies. The model is illustrated by an example application.

AUTHORS

Photios G. Ioannou

Civil & Environmental Engineering Department

University of Michigan

Ann Arbor, Michigan 48109-2125, U.S.A.

e-mail: photios@umich.edu

KEYWORDS

Tunneling, subsurface exploration, geologic exploration, geologic prediction models, probabilistic geologic modeling, Markov process.

AVAILABILITY

Ioannou, P.G., "Geologic Prediction Model for Tunneling," Journal of Construction Engineering and Management, ASCE, Vol. 113, No. 4, 569-590, Dec. 1987.