A new classification of ice failure mechanisms is proposed for vertical pile indentation. It concludes three modes. A block-chart of equations deduced for a designed value of contact force on a vertical pile is presented. The equations are given for the described failure modes.
At present time theoretical and experimental data on the process of the interaction of a separate vertical pile of a structure and moving ice sheet are available. A comprehensive experimental investigation is being carried out to study the mechanism of ice failure by piles. The results of experiments and field observations of cutting through sea ice sheet by piles. With a vertical face have shown that in many cases the ice failure is caused by shear (splitting) with subsequent disturbance of structural rigidity of unsplitted portion of ice sheet.
Based on experimental data and the principles of rigid body failure mechanisms we suggest classification of possible modes (mechanisms) of ice failure by vertical piles considering its thickness H, pile diameter D, ice velocity V and temperature profile of the ice sheet T = f(H). Depending on the combination of the above factors, there may be three modes of ice failure by vertical cylindrical pile of a structure (this form of piles is considered to be the most rational under sea condition). 1. At an ice sheet slow movement and at a relatively high temperature being uniform through its thinkness, the ice will fail by disturbance of its structural rigidity, independently on a pile diameter (Fig.1a). This case is similar to a river ice-structure interaction during spring break-up. Ice forces on a pile may be measured according to the known procedure (Building Codes, 1976).
