Guest Post written by Cabot Martin
My letter of September 11, 2015 to Minister Dan
Crummell, on the perils of a North Spur collapse to workers both on the Spur
and at the powerhouse site across the river, to downstream residents and to provincial
finances alike has, so far, gone unanswered.
Perhaps, that is not surprising. Despite the urgent nature of the
matter, in the past he has usually taken about a month to reply.
One point not fully covered in my letter concerns the
technical analysis on which Nalcor has based its “There’s no problem with the
North Spur“ position. Seemingly, it has been adopted without critical analysis
by Mr. Crummell.
This conclusion was driven home by an article in last Weekend's Telegram (September 18, 2015) reprinted from Happy Valley – Goose Bay’s “The
Labradorian”. That’s the paper that
dismissed award winning journalist Michael Johansen back in November 2013 when
he dared question Muskrat’s fundamentals.
Given that we are all finally getting our minds around the depth
of Nalcor’s incompetence and their
unceasing PR campaign to cover up all things Muskrat in particular, The
Telegram’s decision to reprint an article in which Nalcor V-P, Gill Bennett, takes
off in full and fanciful flight on the lack of risk at the North Spur makes it
timely, yea necessary- to explore the
issue of Nalcor’s much ballyhooed ”Third Party” reviews.
I should say that “fast and loose” is common place when it comes
to the North Spur – in every way.
The Telegram’s North Spur article, referred to above, includes a
photo of the powerhouse construction site on the south side of the river. It
calls the ultra solid rock feature , known as Spirit Mountain, on the far right of the photo “The North Spur”.
Sorry, Telegram…you got it wrong. Spirit Mountain is to the North
Spur as granite is to runny cheese. (Photo not shown in The Telegram's digital version.)
Rather, the downstream side of the North Spur is properly pictured
below.
Now, you
can really see what it looks like – a real pile of unstable garbage –
enough to make any construction type bivver.
The downstream side of the North Spur, September, 2015.
I hasten to add that Mr Bennett’s “Third Party Review”
supposedly offsets, refutes, dismisses, overrides, make a nullity, assigns to
the dustbin of irrelevancy the opinions
of two of the world’s most respected Hydro/Quick Clay experts – James L. Gordon
of Montreal and Dr Stig Bernander of Sweden – the opinions of whom on the North
Spur readers of Uncle Gnarley are no doubt familiar.
Now Gil Bennett’s PR banter can be
taken for what it is – the defense by an
embattled, incompetent corporate bureaucracy of a weak position on a weak Spur.
Rather, it is
the Minister’s position I want to examine.
In the second last paragraph of the Minister’s letter to
me dated August 26th, 2015 he stated that – “The engineering design for the North Spur
stabilization works has been reviewed by three different independent third
parties, who have advised that the design is adequate”.
I can find no corroboration for this statement. I
presume that the three parties are – Retired Professor Izzat Idriss from
California (a seismic expert), Dr. Leroueil from Laval University, and another
whom I am unable to identify.
I have been advised on excellent authority that Professor Idriss did not
produce a report, and only participated in some discussions.
Dr. Leroueil, for his part, produced one letter in
English, just over one page long, and another letter in French. Both are available on Nalcor's website having been first posted by local blogger, Tom Baird, in a piece entitled "On the North Spur". The English version of the second letter is reproduced below, which is an independent, professional translation of the
letter in French.
Dr. Leroueil is very careful in his comments.
In the English letter, dated August 24, 2014, he clearly
states that -
· “my knowledge
on the dynamic behaviour of soils and its analysis is rather limited”. One would expect that a reviewer of a liquefiable soil
would require expertise in dynamic behaviour.
· “Moreover, I
received the main report but not the appendices”. This indicates that the review was not based on all relevant data.
· “Section 2 is
satisfactory to me”…”Stabilization works increase the factor of safety from
about 1.0 to 1.6 which is very significant”. Here Dr. Lerouil has
commented on the conclusions, and has not mentioned that the detailed
calculations, nor whether soil parameters used in the calculations were
reviewed. The soil parameters determine the magnitude of the liquefaction risk,
and are therefore of primary importance.
·
Dr. Leroueil
states that some information is missing in the report, namely –
“I think it
would be good to give factors of safety for the sections 4 and 90 for the
static conditions”.
“more
information is needed on the locations of piezocones”
“what is the NKT
value considered?”.
“I have been
frustrated not to find important figures that are in the appendices”
As stated previously, this indicates the review was
based on incomplete data.
· The sections on dynamic analysis is “interesting”… Not an unequivocal endorsement
of the design.
· In minor comments, Dr. Leroueil states: “I have been surprised to read that “the
granular material can be very sensitive to their saturation” This is true but I am not sure that this
aspect has been considered in the analysis”. This needs to be reviewed
further, as soil parameters dictate safety.
-
The letter, in French , dated 26 October 2014 is more theoretical,
wherein Dr. Leroueil describes the work of Dr. Bernander as “very basic” (not professional?) and
states “to begin [Bernander type] calculations is to begin with many
constraints and questions.”
- He also mistakenly states “
.. that to my knowledge, Bernander’s method” has only been used for the
analysis of existing ruptures, for which the results were already known.”
Nothing could be farther
from the truth.
Dr Bernander’s methodology has been used to explain slides in Sweden that, until then, remained a complete mystery; his analysis was confirmed by a special commission of Inquiry.
Dr Bernander’s methodology has been used to explain slides in Sweden that, until then, remained a complete mystery; his analysis was confirmed by a special commission of Inquiry.
Dr. Bernander is both a respected academic and the former Chief
Design Engineer for Skanska the largest construction company in Sweden with
many, many years of practical experience, something Professor Leroueil cannot
claim.
The rest of the letter is a dissertation on how a failure occurs
and what should be done to improve safety.
Amazingly, far from concluding by saying Bernander is out to lunch, Leroueil concedes that “The disruption can also come from above, for
example through pile-driving, as in the case of Surte researched by Bernander.“
Hence, it is not difficult to identify the source of Minister
Crummell’s empty paradoxical brag in his August 26, 2015 letter that Nalcor is
going avoid “human activities such as pile driving that could induce landslides.”
And by saying “The disruption can come from above” Leroueil is, in
reality, endorsing Dr Bernander’s “Downhill Progressive Landslide” approach,
something that Nalcor has told the Independent Engineer not to look at, as
there is no evidence of such slides in the whole Lower Churchill Valley- the
same Lower Churchill Valley where Dr Bernander on a personal site visit saw all
sorts of evidence of a high potential for Downhill Progressive Landslides.
Crummell doesn’t even know on whose analysis he is acting --- and
who his real friends are. And if he thinks he can sell the idea that all those
excavators and Mack trucks now working on the North Spur, all the digging into
Quick Clay for its “removal” are not as dangerous, and as landslide-inducing,
as a pile driver, then he has more nerve than is good for any of us.
Lacking any information on the third reviewer, and
from the foregoing, it can be concluded that, while in one sense Dr. Leroueil has “reviewed” Nalcor’s North Spur dam safety work, the review is not based on all relevant information, is incomplete, superficial (less than 3
pages) and certainly does
not equal an unqualified
approval of the design.
So, if Professor Leroueil’s less than expert or
considered musings attached are not the “Third Party Reviews” that provide the
foundations of Nalcor’s “What me worry?’ position, where are they?
And, if they do exist, why have they not already been
made public?
And when will they?
The people of Mud Lake await your answer Mr Crummell.
______________________________________________
The following letter is a French to English Translation of a
letter dated October 26, 2014 to Dr. Regis Bouchard from Serge Leroueil on the issue of North Spur
stability found on the Nalcor web site:
Hello Régis,
I haven’t forgotten you, but I was leaving for two weeks of
work with Luciano Picarelli in Naples, and my life was complicated by the fact
that my luggage (and my computer power supply) arrived three days late (no
mistake, the problem was in Toronto!).
Regarding the North Spur, here is my opinion:
-
There is no established methodology for
evaluating stability against a downhill progressive failure. Bernander has
suggested a very basic methodology that, to my knowledge, has only been used
for the analysis of existing ruptures, for which the results were already
known. Ariane Locat has adapted the same method for “uphill progressive
failures”, which has been used to understand two spreads in the sensitive
clays. In my opinion, to begin calculations is to begin with many constraints
and questions.
-
From another perspective, the analytical methods
consist of defining the initial shear stress along the length of a potential
rupture surface, probably mainly horizontal and passing at the base of a slope
in our case. This shear stress is at its maximum at approximately the crest of
the slope. If a disruption increases the shear stress in one spot up to the
soil’s shear resistance, then a progressive rupture can start, and eventually
continue until a global rupture occurs. There are two important points in what
I have said:
1.)
The initial shear stress. If you show that you
have improved the stability of the slope (higher F]), this means that you have
diminished your initial shear stresses and that you move further from the soil
strength (resistance).
2.)
Disruption that can locally increase the initial
shear stress. This disruption can come from above or below. In Québec, the
disruption is most often erosion or a small rupture at the foot of the slope.
However, as you have protected the foot of your slope, you have removed the
possibility of disruption at the foot of the slope. The disruption can also
come from above, for example through pile-driving, as in the case of Surte
researched by Bernander. And there, it has to be demonstrated that you have
taken all the precautions to prevent any disruption at the foot of the slope.
If you improve your stability,
therefore diminishing the risk of progressive rupture with regards to what it
had been, and if you prevent any disruptions, you cannot have a progressive
rupture. I believe this is the way to approach the problem.
Best regards, Serge
_________________________________________________________
Note: the french version of Serge Leroueil's letter dated October 26, 2104 is found on this Link.
