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GeoConSol
Geotechnical & Tunnel Consultants

A consultant is a universal observer who can look at a problem outside the environment in which the problem came to be, thereby creating a solution that was never possible before.  Fernando Flores

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A-Misrepresentations
B-Type 1 or 2?
C-Jacked Pipe Failure
D-Top of Rock
E-PI Litigation Support
F-Geotech Assessment
G-Microtunneling Hard/Soft
H-Machine Failure
I-Boulders-Tunnel Boring
J-Boulders-Microtunneling
K-Plowing Utilities
L-Rock Socket Overrun
M-Bored Tunnel Inflow
N-Rock Comminution
O-Sub-Std TBM Performance
P-Bored Tunnel-Shear Zone
Q-Disputes Resolution
R-Problem Proj. Completion
S-Bored Tunnel Overbreak
T-Auger Sampling Problems
U-Bored Tunnel Delay
V-Hoe Ram - Failure to Rely
Peter J. Tarkoy
differing, site, conditions, overbreak, bored, tunnel, consulting

Overbreak in TBM Tunnel

--- on behalf of Contractor ---

A tunnel in Milwaukee experienced unusual and excessive overbreak, including the invert even though the rock was cut by a tunnel boring machine. 

Although the contractor required only two shifts for the learning curve, their excavation performance was far below expectations.

Anticiapted / Encountered geology, encountered overbreak, and encoutnered TBM performance was presented on a single graphical page as follows:


OUTCOME: Owner settled with Contractor

 
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