What is the correct assumption of the support/restraint acting on a pipe that penetrates through a earth dike with 90% compactness? 2 support have already been provided before & after the bund. Therefore the loads will be carried by these support and not the point where the pipe penetrates. But since the compactness is 90%, will it somehow (point where the pipe penetrates) act as a support? If it is, is it a ystop&guide with 0 mm gap? Since earth dike just containing soil, which might loosen as time goes, can it act as an anchor?

Thank you in advanced

If I understand this, you are saying that your pipe is restrained from sideways motion and vertical motion due to the hole in the dike being about the same size as the pipe that penetrates it. So why not use a lateral and vertical support at two points, one where the pipe enters the dike wall and one at the exit of the dike wall. The stiffness of these supports would be based on the dike wall stiffness at a compaction of 90%. A gap is only necessary if you are sure the hole will open up wider and provide some play. I suspect the dike wall will never act as an anchor unless it undergoes a significant collapse around the pipe.

BUt let say if the pipe just penetrates through the dike, what is the normal practice or assumption at that location? Design wise, since support already provided before & after dike, meaning dike will not act as a support...but since the soil is quite compact, will the dike tend to act as a support??if it will what kind of support?

It could act as a support, and I would use a vertical and lateral support, with or without a stiffness and gap as you decide. If it does not act as a support there will be zero restraint load at that location, otherwise you will see a restraint load, which would prove your assumption -that it doesn't act like a support- wrong.