Modeling hydraulic fracture of glaciers using continuum damage mechanics
Modeling hydraulic fracture of glaciers using continuum damage mechanics
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DOI：
10.1017/jog.2016.68
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发表时间：
2016-08
影响因子：
3.4
通讯作者：
M. Mobasher;R. Duddu;J. Bassis;H. Waisman
中科院分区：
文献类型：
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作者：
M. Mobasher;R. Duddu;J. Bassis;H. Waisman
已知充水裂缝的存在会增加裂缝的渗透深度，并且这被假设为在控制冰山崩解速率方面发挥重要作用。在这里，我们开发了一个连续损伤为基础的孔隙力学配方，使充水的基础和表面决口传播的模拟。该公式将标量各向同性损伤变量纳入冰川冰的麦克斯韦型粘弹本构模型中，并使用有效固体应力的概念来考虑水压对裂缝扩展的影响。我们通过模拟与海洋接触的理想化矩形冰板中的准静态水力压裂来说明该模型。我们的研究结果表明，只有当水压力足够大时，充水的基裂缝才能传播，同时传播的充水表面和基裂缝之间的相互作用可以产生相互积极的影响，导致更深的裂缝传播，这可能会严重影响冰川的稳定性。因此，这项研究支持了水力压裂是冰川加速崩解的一种合理机制的假设。
The presence of water-filled crevasses is known to increase the penetration depth of crevasses and this has been hypothesized to play an important role controlling iceberg calving rate. Here, we develop a continuum-damage-based poro-mechanics formulation that enables the simulation of water-filled basal and surface crevasse propagation. The formulation incorporates a scalar isotropic damage variable into a Maxwell-type viscoelastic constitutive model for glacial ice, and the effect of the water pressure on fracture propagation using the concept of effective solid stress. We illustrate the model by simulating quasi-static hydrofracture in idealized rectangular slabs of ice in contact with the ocean. Our results indicate that water-filled basal crevasses only propagate when the water pressure is sufficiently large, and that the interaction between simultaneously propagating water-filled surface and basal crevasses can have a mutually positive influence leading to deeper crevasse propagation, which can critically affect glacial stability. Therefore, this study supports the hypothesis that hydraulic fracture is a plausible mechanism for the accelerated breakdown of glaciers.