Design of Foundations, Anchored in Unfrozen Ground, To Resist Heaving Forces

In regions where there is deep penetration of seasonal freezing of fine-grained soil there is a serious problem of preventing frost heave of the foundations. A method considered here to provide a stable foundation for the structure is to anchor the footing in unfrozen soil. A foundation anchored in unfrozen ground resists heaving forces generated along the contact surface between the foundation wall and the layer of freezing soil. Before freezing, the load of the structure, the weight of the foundation and the weight of the soil above it are given by the stress acting along the foot of the foundation. When the upper layer of soil freezes heaving forces are generated along the lateral surfaces of the foundation wall which partially or fully counteracts the above mentioned load, thus decreasing or completely cancelling the footing pressure. A further consideration is the inclusion of swelling or "release pressures" beneath the footing when the foundation is being lifted up. Equations are provided to calculate all the forces and to also calculate a factor of safety. Numerical examples complete the presentation. An important factor not considered yet is the question of permissible foundation displacement which will undoubtedly depend on the type of structure involved.Dans les rePeer reviewed: NoNRC publication: Ye