The sewage shaft is underwater

We do not have a backwater valve, but it is certainly a [Revisionsschacht].

The rings were connected/glued together. From the outside, the joints were then sealed.

The requirement is that the shaft cannot fill up with water. However, it does not have to be completely dry.

That's how it looks:

Thank you for your answers.

Hello,

I just had a conversation with our earthworks contractor anyway and asked again.

He said that there are two different systems for the shafts. Either as described by emer and me (i.e., with sealing compound like well foam) or the concrete rings are stacked with a gasket in between (similar to a cylinder head gasket in a car).

The connection should always be relatively tight...

Regards,

Dirk

Now I had the executing company here yesterday and he said he would compact the rings from the inside with mortar.
Is that sufficient and durable?

Thank you very much in advance.