Geologic Prediction Model for Tunneling

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.