Shear‐based fracture propagation in fluid‐saturated porous materials is investigated using a displacement–pressure formulation that includes acceleration and inertial effects of the fluid. Pressure‐dependent plasticity with a nonassociated flow rule is adopted to realistically represent the stresses in the porous bulk material. The domain is discretized using unequal order T‐splines and cast into a finite element method using Bézier extraction. An implicit scheme is used for the temporal integration. The solid acceleration‐driven fluid flow reacts to stress waves, but it results in pressure oscillations. Adding fluid acceleration terms dampens these oscillations and increases the fluid pressure near the fracture tips. By simulating a typical shear fracture case, it is shown that stick‐slip like, or stepwise, fracture propagation occurs for a high permeability, also upon mesh refinement. The acceleration driven fluid flow results in a build‐up of pressure near the fracture tip. Once this pressure region encompasses the fracture tip, propagation arrests until the pressure has diffused away from the crack tip, after which propagation is resumed and the build‐up of pressure begins anew. This results in a stick‐slip like behavior, with large arrests in the fracture propagation. Stepwise propagation related to the initial conditions has also been observed, but disappears once the fracture length exceeds the size of the region influenced by the initial conditions.

中文翻译：

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剪切裂缝传播中的粘滑样行为，包括流体流动的影响

使用位移-压力公式研究了流体饱和的多孔材料中基于剪切的裂缝扩展，该公式包含了流体的加速度和惯性效应。采用具有非关联流规则的压力依赖性可塑性来真实地表示多孔散装材料中的应力。使用不等阶的T样条将域离散化，并使用Bézier提取将其转换为有限元方法。隐式方案用于时间积分。固体加速驱动的流体流对应力波起反应，但会导致压力振荡。增加流体加速项可以减弱这些振荡，并增加裂缝尖端附近的流体压力。通过模拟典型的剪切断裂情况，表明粘滑类似或呈阶梯状，裂缝的传播是为了获得高渗透率，也是在细化网格时发生的。加速驱动的流体流导致裂缝尖端附近的压力积聚。一旦该压力区域涵盖了裂缝尖端，则传播停止，直到压力从裂缝尖端扩散开，此后恢复传播并重新开始建立压力。这导致了类似粘滑的行为，并在裂缝扩展中产生了较大的阻滞。还观察到与初始条件有关的逐步传播，但一旦裂缝长度超过初始条件影响的区域的大小，这种传播就消失了。传播停止，直到压力从裂纹尖端扩散开，此后恢复传播并重新开始积累压力。这导致了类似粘滑的行为，并在裂缝扩展中产生了较大的阻滞。还观察到与初始条件有关的逐步传播，但一旦裂缝长度超过初始条件影响的区域的大小，这种传播就消失了。传播停止，直到压力从裂纹尖端扩散开，此后恢复传播并重新开始积累压力。这导致了类似粘滑的行为，并在裂缝扩展中产生了较大的阻滞。还观察到与初始条件有关的逐步传播，但一旦裂缝长度超过初始条件影响的区域的大小，这种传播就消失了。