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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
boulders, microtunneling, differing, site, conditions, microtunnelling, pipe, jacking, Tarkoy, GeoConSol

Boulders in Microtunneling 
Differing Site Condition

---on behalf of contractor---

Contract called for prices ($/ft) for 15 feet of tunnel in boulders for a 1000 ft long tunnel in glacial till. 

The contractor used a Soltau Microtunneling machine to excavate the tunnel as illustrated below.

The contractor encountered unanticipated quantities of boulders, however, how to identify tunnel sections in boulders?

A combination of samples from the separation plant 

and an innovative use of the microtunneling machine's data logger allowed a demonstration of sections of tunnel which were in boulders as follows: 

A comparison of the anticipated (Bill of Quantities) and encountered length of tunnel in boulders yielded the following results:

With this evidence, the contractor was able to negotiate his costs associated with the unanticipated length of tunnel in boulders.

CONTRACTOR & OWNER SETTLED FOR A FAIR COMPENSATION

 

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