[ANSS-netops] Trillium Compact installation
Mark E. Meremonte
meremonte at usgs.gov
Wed Jul 27 22:33:18 UTC 2011
Hi David,
Here is link from Dupont on its Corian product
that discusses its product. See page 62 in the document:
http://www2.dupont.com/Corian/en_IT/assets/downloads/pdfs/technical/english_2005_dupont_corian_book_techknowhow.pdf
and
http://www2.dupont.com/Surfaces_Commercial/en_US/assets/downloads/pdfs/Corian_Technical_Bulletins/Performance_Properties_of_Corian.pdf.
Thermal expansion
The coefficient of linear thermal expansion for
Corian® is 1 mm per meter. Link to thermal
characteristics that includes concrete &
glass: http://www.hukseflux.com/thermalScience/thermalConductivity.html.
Thus, this is why we have chosen Corian for our
portable vault bases: good thermal stability,
light weight (over glass or tile), less prone to
breakage during shipping and dropping
accidentally, easily machinable, provides
isolation from ground currents similar to glass,
provide flat base to install the small C_Trill,
and is durable (used over & over again).
Once we duct seal the 2 gallon bucket (bottom cut
out) to the vault base, we do have a water tight
seal; and the bucket is tethered to the base w/ 3
tethers (tension of tethers is slight) to insure
bucket is not detached from duct seal during
burial. Bucket has a screw lid with a O-ring;
buckets are food buckets for storing and freezing
food. Buckets are also lightweight and reusable.
We use a bulkhead fitting (designed by Greg
Steiner) to water-tight the cable entry into the bucket.
When we install, we usually put a small layer of
playsand in the hole first to help level and
couple the base in the hole; then pack a bit of
sand around the bucket and base to help anchor
the bucket before packing in the native dirt
around the bucket up to the base of the
lid. Next, install the seismometer, insulate
with fiberglass, add dessicant just below lid
where condensation usually forms, then screw on
lid tightly; then finish burying the system with
at least 6 inches but try to do a foot if
possible for temporary, portable sites.
So far, we have used these vault systems in
Arkansas which CERI installed, in New Madrid, MO,
during the National Level Exercise where it
rained much, in Reno, NV, where we installed 16
stations for a month (but most vaults were duct
sealed to a garage floor or outside concrete
patio w/o trouble, 8 stations along the Calaveras
Fault in mtns for next 6 months to a year
(outcome not known yet), and I tested one for 2.5
months in satellite dish compound at USGS Golden
office (no water contamination).
Attached is a ML3.0 (really 2.98; NCSN) within 15
km of the stations for the Z and N components to
scale, no filtering, for perusal.
Thinking of doing AGU poster on the vault system; better get on the stick.
Best Regards,
Mark
At 18:16 7/20/2011, David S. Croker wrote:
>Thanks Mark (and others). All good
>comments. Looks like we will always have to
>trade ease and cost of installation and
>maintenance with data quality. And
>accessibility (ie, how long does it take to
>uncover the vault when you need to and can you
>get the lid off after its been sitting in the soil for 3 years).
>
>Paul Bodin shared a couple thoughts:
>"That said, based on my previous experiences and
>not ever having used a Tcompact, I nevertheless
>think that direct burial is the most likely to
>be successful. i.e., narrow borehole as deep as
>you can conveniently get (1-2 m?), packed in
>sand. If you put them in a tube, I'd argue for a
>fairly compliant material - i.e. pvc rather than
>steel---and something with a low coefficient of thermal expansivity."
>He also included a rough draft of a paper he
>wrote and submitted to BSSA on "some of the sad
>facts we've learned about long period
>seismometry and vault design over the past
>year." With his permission, I can forward it to everyone.
>
>Dave Drobeck chimed in with similar thoughts as
>Mark and I, and similar concerns that maybe our
>vaults have not been as thoroughly tested as
>they perhaps should be. Sounds like a perfect
>task for Bob. Part of the problem is that no
>one vault is appropriate, or even possible, at all locations.
>
>The difficult thing the NCSN is facing for this
>summer is how to install a C-Trill (or is it
>Tcompact, or Trilco?) in a location where
>metamorphic quartzite bedrock is right on the
>surface and the Forest Service needs us to be as
>discreet and low-profile as possible (forget a backhoe).
>
>Mark, that's a cute little vault you have in the
>attachments. Can you point me to a link that
>shows me what it is? I assume it's water tight? Is the bottom removed?
>
>Thanks again,
>Dave
>
>At 09:58 PM 7/19/2011, Mark E. Meremonte wrote:
>>Hi Dave,
>>
>>For 6 months to a year we use the small vault
>>systems we developed for portable systems: see
>>attachments. For the portables we try to
>>install insulated vaults at least 6 inches
>>below the surface. However, for permanent
>>install I would not install less than a foot
>>below the surface; or, if necessary, we mound
>>at least a foot of soil over top of vault if less than a foot below surface.
>>
>>For permanent I will probably be using a
>>smaller version of our regional vaults with
>>sandblasted glass bases and using
>>insulation. See
>>ftp://ftpext.usgs.gov/pub/cr/co/golden/hazards/Eq_Effects/Vaults/Regional/5_Vault_CMG3-MEMS.jpg
>>
>>
>>Yes, I believe some tests should be done on
>>temperature effects. Similar to other BBs,
>>they should be insulated to stabilize
>>temps. Sounds like an experiment for Bob Hutt at ASL.
>>
>>Some thoughts and Regards,
>>Mark
>>
>>At 15:20 7/19/2011, David S. Croker wrote:
>>>Hi All,
>>>
>>>Simple question with a potentially longwinded
>>>answer (simple answer preferred): What kind
>>>of vault installation do you do for permanent
>>>Trillium Compact sites? Full-blown vaults
>>>with lots of insulation, slightly reduced
>>>scale vaults with a little less insulation, or
>>>simple small scale tubes buried a couple feet
>>>down with minor insulation? How do they respond to temperature changes?
>>>
>>>Thanks for any insight you might have.
>>>
>>>Dave
>>>
>>>__________________________________________________________
>>>USGS - Earthquake Science Center - NCSN Field Operations Manager
>>>David S.
>>>Croker office (650) 329-4697
>>>345 Middlefield Rd, MS 977 fax (650) 329-4732
>>>Menlo Park, CA 94025 cell (650) 465-4334
>>>email: croker at usgs.gov
>>>Quake info: http://earthquake.usgs.gov/
>>>USGS URL: http://www.usgs.gov/
>>>
>>>_______________________________________________
>>>ANSS-netops mailing list
>>>ANSS-netops at geohazards.usgs.gov
>>>https://geohazards.usgs.gov/mailman/listinfo/anss-netops
>>
>>
>>*********************************************************
>>Mark E. Meremonte Geophysicist USGS/ANSS/NEIC
>>
>>U.S. Geological Survey Work: 303-273-8670 Cell: 303-478-5766
>>MS 966, Box 25046 Email: meremonte at usgs.gov
>>Denver, CO 80225 Web: http://geohazards.cr.usgs.gov
>>
>>Ship: U.S. Geological Survey, 1711 Illinois St., Golden, CO 80401
>>**********************************************************
>>
>
>*********************************************************
>Mark E. Meremonte Geophysicist USGS/ANSS/NEIC
>
>U.S. Geological Survey Work: 303-273-8670 Cell: 303-478-5766
>MS 966, Box 25046 Email: meremonte at usgs.gov
>Denver, CO 80225 Web: http://geohazards.cr.usgs.gov
>
>Ship: U.S. Geological Survey, 1711 Illinois St., Golden, CO 80401
>**********************************************************
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