As freezing is occurring, water is drawn to the freezing front by thermodynamic forces. This can produce ice lensing, in addition to phase change. The amount of heave can be considerable, 150 to 300 mm in a season is not uncommon, I have often seen 100 in addition to phase change. For these to happen, all you need is a frost susceptible soil, a lower source of water, and a freezing front. These often show up around water line leaks and frequently cause water line failures as these start to mellow in spring, driving the frost front down further.
When a trench is insulated and drained, through a wet sandy silt deposit, you are designing in a seasonal settlement over the trench, in addition to any line settlement.
Look, ... there goes a rabbit.