Lol, you think a parking lot needs 5m of vertical fill? No, this is for heavy foundations. They'll need another logistics yard for the 2M Models 2 per year that Phase 3 will be cranking out by 2024-ish.
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I hope by 2024 Tesla FSD can automate much of the factory-lot logistics. Would be especially nice to see new cars drive themselves to the Port, or even onto tractor-trailers.
Cheers!
What is happening here is a pretty common operation in my world.
The trucks are bringing in material to allow the excavators/bulldozers to build out a working pad in the marshy area. You can easily observe the existing soil is highly saturated and the ground water elevation is quite high. It would be entirely unsuitable for even tracked equipment cross this area, and it's not the sort of thing you want to, or even could build on. This operation accomplishes two things:
1. It establishes a more suitable working elevation for the future infrastructure that is above the existing water table, and some sort of flood level design elevation (1 in 100 year flood event for example)
2. It levels the site to provide a flat* area to build on.
*flat actually means positive drainage, in that rainfall will not accumulate as standing water, assuming this is not meant for a building. You'll recall Giga Texas had issues right before they were installing the raft slabs where the flat site did not shed water well. The site had to be flat as a sloping factory floor is... not ideal, but it's what you want in a parking lot or road.
Typically, when "padding" out across marshy/muskeg areas, the first lift may be well in excess of a meter as it simply isn't possibly to achieve any sort of compaction with the water saturation level so high. I've padded out into way worse than these conditions, they haven't even sunk any machines! Another reason for padding out a site is because water is a newtonian fluid therefore and cannot be compacted, so it is a fruitless effort to attempt to compact anything lower than the water table, which is why you want to build things above it, unless you are in a different branch of Civil Engineering.
They will need to finish levelling the entire site before whatever comes next. I suspect we'll see the start of something here in the next month or so.
@Maarten is factually correct with his explanation of pre-stressing or "pre-load" in North American vernacular, but pre-load this is not. Pre-load needs to be installed in "lifts" or layers of material, this is being bulked in, there isn't a compactor in sight anywhere. For reference, 5m of vertical fill is a medium preload height. I've currently got several 13m vertical preloads in various states of settlement on my project. It is not uncommon to have factories/warehouse pre-loaded for years, as
@Maarten suggests, but it really depends on a lot of things. I've seen pre-loads as short as several weeks and a long as 3 years. Think of it as squeezing a wet chamois into a ball. It's rather useless when wet, but turns stiff and rigid when the water is squeezed out.
Preload may indeed be required in this area, but it depends on what they intend to construct. Point loads from heavy equipment and machinery are typically handled by piled foundation in situations with insufficient bearing capacity or if you want to do it quickly. I believe the first round of Shanghai had a lot of piling rigs at one point. Texas did not. Spread footings can also work, it depends on a lot of factors, the idea is either lower the pressure or ensure that whatever you're installed won't move over time.
