A non-local continuum poro-damage mechanics model for hydrofracturing of surface crevasses in grounded glaciers
A non-local continuum poro-damage mechanics model for hydrofracturing of surface crevasses in grounded glaciers
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DOI：
10.1017/jog.2020.16
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发表时间：
2020-04
影响因子：
3.4
通讯作者：
R. Duddu;S. Jiménez;J. Bassis
中科院分区：
文献类型：
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作者：
R. Duddu;S. Jiménez;J. Bassis
水力压裂可以增加裂缝传播的深度，在某些情况下，允许裂缝穿透和冰山分离。然而，许多现有的决口模型要么不完全考虑驱动水力压裂过程的应力场和/或将冰川冰视为弹性的，忽略了非线性粘性流变学。在这里，我们提出了一个非局部连续介质孔隙损伤力学（CPDM）模型水力压裂，并实现在一个完整的斯托克斯有限元公式。我们使用CPDM模型来模拟理想化接地冰川中充水裂隙的传播，并将该模型预测的裂隙深度与线弹性断裂力学（LEFM）和零应力模型预测的裂隙深度进行比较。我们发现，CPDM模型是在很好的协议与孤立的裂缝和零应力模型的LEFM模型紧密间隔的裂缝，直到冰川接近浮力。当冰川接近浮力，我们发现，CPDM模型不允许水填充裂缝的传播，由于尺寸小得多的张应力区域集中在裂缝尖端附近。我们的研究表明，充满水的裂缝尖端附近的冰中非线性粘性和损伤过程的结合可以改变崩解结果。
Hydrofracturing can enhance the depth to which crevasses propagate and, in some cases, allow full depth crevasse penetration and iceberg detachment. However, many existing crevasse models either do not fully account for the stress field driving the hydrofracture process and/or treat glacier ice as elastic, neglecting the non-linear viscous rheology. Here, we present a non-local continuum poro-damage mechanics (CPDM) model for hydrofracturing and implement it within a full Stokes finite element formulation. We use the CPDM model to simulate the propagation of water-filled crevasses in idealized grounded glaciers, and compare crevasse depths predicted by this model with those from linear elastic fracture mechanics (LEFM) and zero stress models. We find that the CPDM model is in good agreement with the LEFM model for isolated crevasses and with the zero stress model for closely-spaced crevasses, until the glacier approaches buoyancy. When the glacier approaches buoyancy, we find that the CPDM model does not allow the propagation of water-filled crevasses due to the much smaller size of the tensile stress region concentrated near the crevasse tip. Our study suggests that the combination of non-linear viscous and damage processes in ice near the tip of a water-filled crevasse can alter calving outcomes.