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Re: Frozen soil = disturbed earth?
- To: seaint(--nospam--at)seaint.org
- Subject: Re: Frozen soil = disturbed earth?
- From: Stan Caldwell <stancaldwell(--nospam--at)gmail.com>
- Date: Tue, 24 Mar 2009 17:00:02 -0500
Your post did not bore me! Instead, it brought back a flood of memories. I arrived at Prudhoe Bay, on the Arctic Coast of Alaska, in May 1971. As an ARCO engineer, I spent much of the next seven years working on design, construction, trouble-shooting, and research projects up there. Prudhoe Bay sits on about 2000 feet of unconsolidated permafrost that, if thawed, would be about like a Wendy's Frosty. All roads were five feet thick of gravel, which was necessary to equal the thermal properties of the few inches of native Tundra grass that were being covered up. All of our enclosed facilities were elevated several feet and supported on piles to keep the permafrost frozen. Initially, we used cast-in-place concrete slabs on timber piles. Eventually, we switched to huge modular units constructed in the Lower 48 and barged up to the site. The modules were always supported on steel pipe piles. Either way, the piles were installed in augered holes and then backfilled with a engineered sand/water slurry. The design criteria was adfreeze (think skin friction) with a big margin of safety to prevent/minimize long term creep. Frost heave uplift was also a consideration.
Prudhoe Bay has only two seasons: Frozen (long) and Mosquito (short). All off-road and off-pad work was done in the Frozen season, when temperatures regularly hovered around -60 Deg.F, excluding wind chill. The first thing you learn is not to drink much liquid at breakfast, because ARCO's standard Arctic trousers had metal zippers (use your imagination). Care was also necessary because some metals became brittle at those low temperatures. Also, during Frozen season, it is dark, pitch dark with not a glimpse of twilight, 24 hours a day. My most memorable project involved test driving and then pulling sheet piling at a gravel spit five miles offshore in the Arctic Ocean. I drove to the site every day in my pickup truck. The diesel hammer would not ignite on diesel or naptha, so I ended up ordering a plane load of ether (carburetor starter fluid). Day after day, another engineer and I would take turns climbing up the trestle and squirting ether into the hammer on every stroke. We successfully drove the piling and pulled it, demonstrating that it did not roll up (scroll) as had been predicted. That allowed ARCO to subsequently drive sheet piling around the perimeter of the gravel spit, fill it with gravel to create a drilling pad, and complete the first exploratory oil well in the Arctic Ocean.
Why was this memorable? There were two unforgettable mishaps. One evening, everyone left the site ahead of me and I drove back to the base camp all alone. About half way to shore, my truck slid into an open lead. There I was, all alone in the dark, with the water quickly refreezing all around me. Thanks to four-wheel drive and a Wisconsin upbringing, I survived and so did the truck. A few days later, while up on the pile driving rig for an extended period, I managed to freeze both feet. It turned out that ARCO had inadvertently issued me safety boots, with integral steel toes. Back at base camp, I explained to the medics that I had no feeling below my ankles and admitted that I had also frozen my feet once previously on an ill-fated high school ski trip. They promptly shipped me back to Dallas, where they told me that I could look forward to a double amputation. I went back to work on crutches and never went to a doctor. About three months later, my feet more-or-less returned to normal. It has been 36 years, and I still have the proper number of feet and toes.
Now then, I hope that I haven't bored you!
If you're not a liberal when you're 25, you have no heart.
If you're not a conservative by the time you're 40,
you have no brain. ... anonymous