Level a hillside plot with excavation (clay soil)?

I am still planning my construction project and am gradually starting to think about requesting the earthworks for the excavation pit. In this context, a trench for geothermal collectors is also to be laid.

My property has a slight slope from west to east (approximately 1.0 - 1.5 meters difference in height over about 25 meters width). I had considered retaining the property on the east side with a natural stone wall about 25 meters long (this would slowly increase in height towards the south, ending at about 1 meter to max. 1.5 meters high). The rest of the property could slope gently towards the south, where there is a green strip about 15 meters wide owned by the municipality. If the municipality objects to this, I would possibly also retain this with a natural stone wall.

My plan would be as follows:
1. Excavation for the trench (total approx. 60 meters long, 1.75 meters deep, 2 meters wide)
2. Lay and secure brine pipes in the trench
3. Backfill the trench and excavate the construction pit
4. Level the property with the excavation soil from the construction pit (hold back some for backfilling)
5. Build the natural stone wall and possibly adjust again

Does this procedure make sense? And if so, how should I handle the topsoil? Remove it completely and set it aside to redistribute it later over the clay soil? (With 800m² of land, that amounts to quite a lot).

You can do it that way. However, the question is whether you will be happy with clay soil as excavation material - keyword: infiltration of rainwater. I would have the clay excavation disposed of and have reasonable fill soil brought in (or have it brought in). We also struggle with clay soil here; on some currently still undeveloped plots, practically no infiltration of rain occurs anymore after a certain saturation of the soil. If no measures are taken there, you will have a lot of fun in the garden later...

Hello,

with a potential fall height of 1 m - 1.5 m, you will probably not be able to avoid a fall protection.

This should also be planned (and calculated) right from the start.

Regards,

Dirk

You can do it that way. The question, however, is whether you’ll be happy with clay soil as excavation – keyword: infiltration of rainwater. I would have the clay excavation removed and proper fill soil brought in (or have it done). We also struggle with clay soil here; on some currently still undeveloped plots, practically no infiltration of rain occurs after the soil reaches a certain saturation. If you don’t take measures there, you’ll have a lot of fun in the garden later...

I feel the same way.

We also had clay soil in parts. I disposed of the excavation.

In the garden, I also had a good amount of proper fill soil brought in under the topsoil humus (you usually get the material for free). Of course, not because I knew about it. But the people who did it knew what they were doing, and in hindsight, they were right. That’s how infiltration works and everything I planted has so far grown to >99%.

Best regards
Thorsten