This paper studies the effect of stress inhomogeneity on the behaviour of fluid-driven fracture development in weakly consolidated granular systems. Using numerical models we investigate the change in fracture growth rate and fracture pattern structure in unconsolidated granular packs (also refered to as soft-sands) as a function of the change in the confining stresses applied to the system. Soft-sands do not usually behave like brittle, linear elastic materials and as a consequence, poro-elastic models are often not applicable to describe their behaviour. By making a distinction between “cohesive’’ and”compressive’’ grain-grain contact forces depending on their magnitude, we propose an expression that describes the fluid opening pressure as a function of the mean value and the standard deviation of the “compressive stress’’ distribution. We also show that the standard deviation of this distribution can be related with the extent to which fracture”branches’’ reach into the material.

中文翻译：

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应力不均匀性对弱固结颗粒体系中流体诱导的断裂行为的影响

本文研究了应力不均匀性对弱固结颗粒系统中流体驱动裂缝发展行为的影响。使用数值模型，我们研究了未固结的颗粒状包装（也称为软砂）中裂缝生长速率和裂缝模式结构的变化，该变化是施加于系统的围压变化的函数。软砂的行为通常不像脆性的线性弹性材料，因此，孔隙弹性模型通常不适用于描述其行为。通过根据其大小区分“内聚”和“压缩”晶粒接触力，我们提出了一个表达式，该表达式将流体开启压力描述为平均值和“压缩应力”标准偏差的函数。 ''发行。