Loading Mechanisms in Thawed Permafrost Around Arctic Wells

Four permafrost thaw-subsidence loading mechanisms are described for inducing casing strain. Phase change contraction in ice rich soil and consolidation with fluid flow are more likely to occur in surface and near surface soils. Stiffness reduction and pore pressure reduction are important in deep permafrost and generate body force-type loads. The equations for stiffness reduction loading are presented in terms of an elastic model. The effects of lithology and thaw variations on casing loads are examined in the context of the four mechanisms.