I don't think I would have even thought to worry about the ice causing a problem. I think the physics are on your side. If the pipe is round then any pressure pushing in on the pipe will be evenly distributed. Under those conditions a pipe is very strong. Also under pressure ice melts so it will probably liquify around the pipe. If there is a net inflow of water into the pond then it will start to seep around the edge of the pipe melting it further. Even if this does not occur any buildup of water will raise the ice a little but will eventually start running over the top of the ice. I have seen this happen.

I had a permanent 4" white PVC siphon set in my pond. They finished the pond in the fall. The pipe runs from the dry side of the dam about six inches below the dirt to the wet slope remaining underground. It then pops out of the side about four feet above the deepest part of the pond and runs horizontally for about fifteen feet before plunging straight down about four feet and then curving up. The water was about 3 feet deep and froze to a foot thick. Water was running in and sometimes the ice was stuck to the sides and the water would go on top of the ice. Sometimes the ice would break free and rise with the water. I never did pull the pipe up (it was weighted with stones below water). When the ice had risen to just below the horizontal section I got frightened that it might rest on the ice and lift up. So I cut the ice to make it thinner and put salt on top of the whole length of the pipe. The pipe never did damaged even though I could only visit it once a week.

I think if there is flowing water you shouldn't have a problem. Is this something you have had happen already or are you theorizing?

PS. I don't know what would happen with corregated pipe. Although I think pressure would again melt the ice. The pressure thing does not work as well as the temperature drops so you might still have a problem with how far north you are. I am in NY and that was a particularly cold winter I was describing.