Groundworks have not started - too wet?

Hello everyone,

I couldn’t find a specific subforum for groundwork / foundation, so I’m posting it here:

We are about to build our house in the Elbmarsch (distance to the dike approx. 1km) and are therefore dealing with problems related to high groundwater and damp soil. Our plot has to be completely raised by 60cm, the groundwater level determined in the soil report lies (before the filling) at approx. 0.5m. Furthermore, due to the soil conditions, the recommendation has been made to pour a stiffened slab foundation.
With our general contractor, we have contractually agreed on the following groundwork: stripping of the topsoil by 40cm and compacted installation of a sand slab with a height of 1m.

The soil structure is as follows:
up to 0.4m: sand, silty, humus; designation: topsoil
up to 0.8m: sand, silty; designation: sand
up to 2.5m: medium sand, coarse sand, weakly fine sandy; designation: sand
up to 3.0m: silty clay, humus, weakly sandy; designation: clay
From this follows the recommendation to pour a stiffened slab foundation.

Now to the problem:
Due to the enormous rainfall in February, standing water was on the plot about two weeks ago. The earthworker then refrained from starting the groundwork because he saw no possibility of installing the sand.
Since the weather has improved in the meantime, the top 10cm are now “dry.” Nevertheless, yesterday came the statement again that a start of construction is not possible and that at least two more dry and sunny weeks are needed.

Therefore, the following questions:

[*] Is it generally impossible or not recommended to install sand if the lowest 30cm cannot be compacted dry?
[*] Would it possibly be even feasible to skip stripping the topsoil and merely apply a sand slab of 60cm? I suppose that would probably have to be answered by the soil expert, right?
[*] Any other possible solutions without carrying out an elaborate groundwater lowering or similar?

Thanks in advance!

Regards,
Mirco

2. Would it possibly even be feasible to do without removing the topsoil and instead only apply a 60cm sand layer? I suppose the soil expert would have to answer that for me, right?

I think this question has actually become obsolete. At this point, I would like to dismiss the idea of foregoing the removal of the topsoil.

Hello Mirco,

Now to the problem:
Due to the enormous rainfall in February, the property was covered with standing water about two weeks ago. The earthworker then refrained from starting the groundworks, as he saw no possibility of installing the sand.

What the users of this forum consider _possible_ or not does not help you, because in the worst case they owe you no warranty.

I can well imagine that it is annoying for you to watch time pass by without anything changing on your property. BUT – your civil engineer is also responsible for ensuring that the foundation permanently supports the load of your single-family house. Therefore, trust him; in my opinion, he knows what he is doing or refraining from.

See it as a "trial phase" for the later drying time of the screed; during this time you can do nothing but wait as well.

Rhineland regards

If I imagine compacting absolutely soaked sand.. Splash splash. Better wait.