Unusual phenomenon magnetic fields

Thread Starter

WM1205

Joined Dec 10, 2018
7
Hi, I made mention of this situation in another category in the site but it is more likely suited to be posted here.

Also of notable interest I was a Project Manager working with a roadside reinforcement operation about 6 years ago we were stabilizing a road which was built atop a old wash pond from a sand and gravel operation in the late 1900's on the side of a mountain Northern Pennsylvania near NewJersey, we were Drilling on a slope adjacent to the area that fell; the entire road pretty much sank into the mountain side thus blowing out the toe of the slope 20' down the embankment from where the road originally started elevation wise (I know your thinking what the hell does this have to do with the conversation... let me finish as details are of importance to what we saw at this particularsite) so the solution was to drive 1441 steel casing 8" od × 0.750" wall in at 4' spacing along the road hillside x 40' deep [2] 20's welded together with 0.125" 1018 arc rod. The casing minimum reveal was 6" from the surface after being driven to refusal. We welded 1" x 8' x 6' plates to these casings so that 2 casings were fastened to each plate after 4 of these units were assembled we started having issues with the drills particularly on the computer controller side and had to switch from remote control to manual to continue there is 1600' of these assemblies installed at this location next we used a grout pump to inject each case via atremmi tube to force the grout from the bottom to the top under pressure to form a lollipop on the end of the case. Next we connected the plates together with fiberglass rebar and a ground ring zinc coated copper 0.50"dia was embedded in the area around the plates. Following the installation of the grounding ring is where things got weird, we poured the containment wall atop the fiberglass cage and ground ring the concrete was a special mix that contained #300 mesh Aluminum powder to react with the lime and generate hydrogen gas I believe which in turn caused the concrete to heat up and foam up similar to spray foam this was an intentional response what was weird was the following day when we went down to strip the forms off, anything that was made of iron/steel had vibrated when placed onto the foam concrete structure and where the joints exist below thepoor is a stranger phenomenon yet when you place a aluminum/brass wrench atop at these joint locations the wrench vibrates and turns slowly back and forth as though someone isturning it on the surface... Naturally I tried other experiments while I was there too. Next there was a class triple A super A cap pouredon top to protect the superlight retaining wall below and cast into this section is a epoxy coated steel rear cage with guide rail platesattached. And also the road was eventually finished with many unforeseen events and issues alike. With the cap in place the strange magnetic fields seemed to subside atop the structure however other oddities arose.
 

Alec_t

Joined Sep 17, 2013
12,148
the strange magnetic fields seemed to subside atop the structure
How do you know they were there previously? Did anyone actually do any magnetic measurements? The motion of the wrenches etc could have had other causes (e.g. minor earth tremors caused by the landscape alterations).
 

Thread Starter

WM1205

Joined Dec 10, 2018
7
Please pardon my many grammatical errors as I am posting with my note 8 and I did not proofread before posting.my apologies to whom this may offend. Another instance at this site was following the retaining wall operation we then shifted to the soil nail operation on the uphill side of the jobsite this consisted of 3 soil nails consisting of a case which was drilled down into what was assumed to be bedrock, a socket was formed the tremmi tube assembly was installed with a 2"dia cable with a 2.750" threaded rod at the end, the case was withdrawn as the grout was injected at 30°, 60°, and 90° into the embankment surface at 6' apart for 2100' lenial, the drilling went well for the first set of 8 then our remote issue again had come back so again we switched back to manual drilling, so we continued with the installation process, next we installed a heavy corrugated plastic mesh over the finished portions with heavy zinc galvanized wire gabbion cages inserted over the protruding threaded rods, the gabbion cages were then filled with #3 ASSHTO stone and the tops were crimped shut where the threaded rods protruded the gabbion blocks steel plates 16"sq x 1" thick also heavy zinc galvanized were bolted on with heavy zinc galvanized snap serrated washer and large 3.25" x 6" nut. We used a torque multiplier with a hydraulic wrench to tighten the nuts to 300Kips and then the secondary protection cage was added to the face of the gabbion assemblies and a wall of Tripple A Tripple Accelerated concrete was used, we sealed 4 units at a time in this process, and again at the unseen joint points the magnetic phenomena arose again. So during break we tried different things and metals to see the behavior and it was quite interesting, the area between these two structures exists Absolutely no cell phone reception, outside of it in either side you get 4g 5bars, as you walk in from either side the signal slowly decreases until you hit what we call the 200' mark from either side same effect jump the wall at any point reception goes right up. Another instance is xm radio is also blocked at the 460' mark on either end, same with 2 way radios. Another anomalie is the voltage measurements between "some" of the soil nails not all of the nails exhibited this. Any thoughts as to the cause?
 

Thread Starter

WM1205

Joined Dec 10, 2018
7
How do you know they were there previously? Did anyone actually do any magnetic measurements? The motion of the wrenches etc could have had other causes (e.g. minor earth tremors caused by the landscape alterations).
I did use my minlab vlf metal detector at the site prior to the start of construction and it did work quite well having known about the "sand and gravel pit" operated at the location and other geological evidence that suggested it would be a good area to scan. Normally the minlab vlf is very finicky and does not operate well in areas with high magnetic fields. As I also scanned or I should say tried to scan the area following the retaining wall operations well after the job was completed and the detector did not work very well at all, I assumed it had been because the surface ground my be highly mineralized as a result of the drilling fines, so I made several passes with a magnetic broom that I made from a earlier project for collecting meteorites utilizing 15 4" x 4" x 8" N52 magnets that I acquired from K&J a ways back, then I gave it a go again and had the same results
 

jpanhalt

Joined Jan 18, 2008
11,088
Small geography "correction" -- I would consider the Pennsylvania-New Jersey border to be South and Southeast of Pennsylvania. North and Northeast are New York.

Pennsylvania is honeycombed by coal mines. Subsidence is a concern in many areas. How do you know that the percolating behavior of your concrete combined with drilling and hammering over an unstable subsurface didn't cause longer term adjustments of the terrain (also suggested by Alec t)?

Finally, I am skeptical that the evidence points to magnetism. Did a magnetic compass in the area show strange deviations?
 

Thread Starter

WM1205

Joined Dec 10, 2018
7
Small geography "correction" -- I would consider the Pennsylvania-New Jersey border to be South and Southeast of Pennsylvania. North and Northeast are New York.

Pennsylvania is honeycombed by coal mines. Subsidence is a concern in many areas. How do you know that the percolating behavior of your concrete combined with drilling and hammering over an unstable subsurface didn't cause longer term adjustments of the terrain (also suggested by Alec t)?

Finally, I am skeptical that the evidence points to magnetism. Did a magnetic compass in the area show strange deviations?
 

Thread Starter

WM1205

Joined Dec 10, 2018
7
This particular area is in bounds with Northern Pennsylvania and New Jersey as stated and as for the coal mining this particular area is completely devoid of it. The concrete was completely cured at time of the observations, and as for hammering the condition was non existent as we were using sonic drills which are intended to keep the subsurface intact and undisturbed as with that would be the case with traditional Drilling methods the bearing compasses on the drill rings were just flipping around randomly we used good-ole'fashioned string lines to stay on target after the anomalies started
 

jpanhalt

Joined Jan 18, 2008
11,088
Added thought: The aluminum powder/lime reaction that results in oxidation of the aluminum and production of hydrogen gas is an electrochemical cell and would produce an electrical current. If viewed as a battery, the aluminum would be the negative terminal. Given the construction details, which I do not completely understand, there could be electrical currents, as the rods into the ground would be "earths." Electrical current produces magnetic fields, and such fields might be detected by a compass.

Whether those fields would be strong enough to effect the described behavior of wrenches and such, I do not know. Seems unlikely, but then, the scale of that project was considerably larger than any construction project I have undertaken.
 
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