\My guesstimate is that once this shield is made, some do-gooder will take it to other jobs and maybe add to it. So, don't pinch on strength. Over building won't hurt and maybe it won't be ruined on the jobs due to skimpy construction. They don''t get much care in use, so build it accordingly.
don't make the mistake of jetting that fill. You could cave in the basement wall. I'd keep compactors 3 feet from any basement wall to avoid damaging them.
Take at look at USA Corps of Engineer projects for piers and walls using circular sheetpile sections tied together with sheet piles. Not cheap, but effective.
All these ideas are Pretty damn elaborate and difficult to do. One initial comment, be sure any drain is properly filtered. The easiest is a simple perforated pipe, with 1/8" holes backfilled with ASTM C33 concrete sand. Forget the gravel unless it is wrapped with a filter cloth (takes time...
You are correct with this question. Sounds like a inexperienced engineer is asking for this sort of test sample. I can't visualize how any accuracy or dependability is there when using a highly disturbed of such a small diameter. Both rather stupid.
Could be an ash dumped. I had a job nce where one sample was thought to be a natural deposit. However the job insector identified it as coal ash, meaning the who9le site was underlain by dumped coal ash, not discovered as ssh in the test borings. That inspector saved a lot of grief...
A very difficult thing to work with, especially where the voids can be very deep like 100+ft.
I'd sure like to see how someone overcomes that situation. I gave up on a few jobs and they went to a lighter project with many spans over voids.
I'd not compact in the usual way. I'd use a loading machine and push it down, no disturbance like compacting. leave the load on when checking the head loss with water going thru, etc.
Go on line and look up ASCE. The you will get lots of information. It's not the highest paying engineer jobs, but sure has a lot of different fields to work in as a CE.
I founa Masters helped me very much to get a jump on the graduates.
For that drain, don't forget to encase any gravel backfill with filter fabric OR use concrete fine aggregate for the drain backfill to keep from losing soil into the drain and beyond. Single size gravel is not a filter.
If you keep the water content of the concrete just enough to place it, shrinkage is likely no probe's. Notice I didn't say Pour the concrete. Use a vibrator to assist in placement. Then either way for getting that support will work. If in doubt go with dry pack well after concrete sets.
I once had the job of evaluating the support capability of a corrugated galvanized culvert pipe of damaged oval shape used as a pedestrian tunnel within the backfill of a railroad bridge. There was measurable deflection of this culvert pipe as a train passed over. Amazing that the diesel...
