  There is a need for computational models capable of predicting
meltwater-assisted crevasse growth in glacial ice. Mass loss from glaciers and
ice sheets is the largest contributor to sea-level rise and iceberg calving due
to hydrofracture is one of the most prominent yet less understood glacial mass
loss processes. To overcome the limitations of empirical and analytical
approaches, we here propose a new phase field-based computational framework to
simulate crevasse growth in both grounded ice sheets and floating ice shelves.
The model incorporates the three elements needed to mechanistically simulate
hydrofracture of surface and basal crevasses: (i) a constitutive description
incorporating the non-linear viscous rheology of ice, (ii) a phase field
formulation capable of capturing cracking phenomena of arbitrary complexity,
such as 3D crevasse interaction, and (iii) a poro-damage representation to
account for the role of meltwater pressure on crevasse growth. A stress-based
phase field model is adopted to reduce the length-scale sensitivity, as needed
to tackle the large scales of iceberg calving, and to adequately predict
crevasse growth in tensile stress regions of incompressible solids. The
potential of the computational framework presented is demonstrated by
addressing a number of 2D and 3D case studies, involving single and multiple
crevasses, and considering both grounded and floating conditions. The
computational framework presented opens new horizons in the modelling of
iceberg calving and, due to its ability to incorporate incompressible
behaviour, can be readily incorporated into numerical ice sheet models for
projecting sea-level rise.
