keeping an eye on yurt platform

[Larzo]

My

yurt platform

is a few feet off of the ground. I noticed that a few of the supports are not 100% vertical but have a very slight angle to them. Most of the others appear vertical from looking at them just by eye. The slanted ones are closer to the door which is to the left in these photos.
The yurt is 5 years old


I am not sure the dynamics of how the platform works. I considered adding a few or a bunch of additional supports myself. However, I don't know if the spacing of the supports is such that if I add others would I disrupt some kind of natural support dynamic. This is a 20 foot yurt and maybe there are 12 supports. I am not sure, I should have counted. If I try to adjust the existing supports, it's not clear if they are well settled and I might not go about it the best way in that case and destabilize them.

I could easily cut some new supports and use a car jack to jack up the platform in a few spots just a tiny amount so I could add some new supports, possibly using some thin boards as shims if needed. If I did it in such a way that there was more supports in one area rather than an even distribution of supports as is currently, I am not sure if that is the best either ..

The spot the yurt is at can get pretty wet in the spring and it is probably on clay.

there is black plastic sheets around much of the uphill side and on the side where the picture is which you can plainly see. I put it there to kill of Japanese Knotweed because it was growing there. The site was a landfill at one time and that is why it was growing there probably. However, I may leave the plastic sheets because I read someplace that things of this sort can help reduce the risk of frost heaves in the ground which can disrupt structures. There is no plastic on the opposite side or on the downhill side.

It seems that my platform is very deck like in that it has the same kind of footers. I have researched decks online and decks can have alot of problems with shifting soils. The yurt round shape may mean there is some difference on weight distribution perhaps but I am not too sure if that is very significant or not