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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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
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
hoe, ram, hydraulic, impact, hammer, massive, rock, Charles, Merguerian

Impact Hammer / Hoe Ram - Failure to Rely on Indicated Conditions 
---on behalf of the owner---

What happens when your consultant misrepresents the indicated conditions of a contract you are bidding?  

"Manhattan Schist" or the schist in Manhattan (regardless of what it is called) of New York City is known to contain both gneiss and schist continually alternating within centimeters, contrary to the testimony of the contractor's expert,  Charles MerguerianMerguerian's report and testimony contradict his own publications.  Manhattan schist has more than a 100 years of construction history and experience, it is hard and massive, as illustrated in the tunnel below......

and weathered only near the top of rock and along shear zones.

A contractor failed to examine the massive nature of the Manhattan Schist rock as  illustrated by the project's massive core.................. 

the high RQD reported in the rock core borings, 

and warnings of massive rock by contractor's own engineer. 

Despite all of this evidence, the contractor claimed he expected to easily and at  a high rate of productivity comminute the rock with an impact hammer.

He was not very successful as illustrated here...

The contractor's expert, Charles Merguerian provided a report entitled: 

"Petrographic Analysis for Rock Mass Characterization" 

in an attempt to indicate that the encountered rock was gneiss rather than schist and therefore more massive than indicated by the well-known term of "Manhattan Schist".  

It is impossible to characterize this rock mass....

through a 

microscope ! ! ! ! ! ! ! ! ! ! ! ! !

  Needless to say, the Disputes Review Board found against Merguerian's theories.

For more details click here.