Another is underground tunnel building. In sandy places, there are cases where they freeze the ground when building a concrete structure. If that could be reinforced with stronger ice, it might make working easier.
Similar, you can use ice as an temporary scaffold when e.g building a spanning bridge in winter. Stronger ice => easier application of said scaffold.
(I'm telling you I'm from southern California without telling you I'm from southern California)
I live in MN and have slept overnight on the ice (inside of a heated trailer) before.
Obviously you know better than I do, but I'm literally uncomfortable here in bed just reading about skating over ice that thin. I'm going to go think about something else now...
Ask them how big and how many stones they have to skate by that are clearly thrown by people from land who are unsure if the ice is thick enough despite a stone larger having already been thrown.
(one of, if not the most experienced ice skater in the world having a blast)
With no concrete or steel required, and with ice and plant-based cellulose as the main ingredients, this could be a building material with a low carbon footprint that's also biodegradable."