Abstract Geomaterials containing fissures such as some sedimentary rocks often exhibit a bimodal pore size distribution, and they are also inherently anisotropic due to the distinct bedding planes. Hydromechanical modeling of solid deformation and fluid flow of such geomaterials remains a significant challenge. In this paper, we have developed a unique anisotropic double porosity elastoplastic framework to describe such processes. Furthermore, for the solid constitutive model, because of the loss of stress tensor coaxiality between the trial state and the final state, we have derived a new implicit return mapping algorithm to obtain the updated effective stress, history parameters and consistent tangent operator for any given strain increment efficiently, followed by a uniaxial strain point simulation to provide benchmark results. Subsequently, 3D stress point simulations are carried out to calibrate the projection and plasticity parameters using triaxial experimental data as well as to illustrate the strain-softening phenomenon. Initial boundary value problem simulations have been conducted to analyze the impacts of fluid flow and solid constitutive model on the resulting geomaterials’ responses. The overarching goal of this paper is to better understand the coupled solid deformation-fluid flow in the transversely isotropic fissured rocks.

中文翻译：

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横向各向同性裂隙岩中固体变形和流体流动的流体力学模拟

摘要 一些沉积岩等含有裂隙的岩土材料往往表现出双峰孔径分布，而且由于层理面不同，它们也具有固有的各向异性。这种地质材料的固体变形和流体流动的流体力学建模仍然是一个重大挑战。在本文中，我们开发了一种独特的各向异性双孔隙弹塑性框架来描述此类过程。此外，对于固体本构模型，由于试验状态和最终状态之间应力张量同轴度的损失，我们导出了一种新的隐式返回映射算法，以获得更新的有效应力、历史参数和任何给定的相切算子。有效地增加应变，然后进行单轴应变点模拟以提供基准结果。随后，进行 3D 应力点模拟以使用三轴实验数据校准投影和塑性参数，并说明应变软化现象。已经进行了初始边界值问题模拟，以分析流体流动和固体本构模型对所得岩土材料响应的影响。本文的首要目标是更好地理解横向各向同性裂隙岩中的耦合固体变形-流体流动。已经进行了初始边界值问题模拟，以分析流体流动和固体本构模型对所得岩土材料响应的影响。本文的首要目标是更好地理解横向各向同性裂隙岩中的耦合固体变形-流体流动。已经进行了初始边界值问题模拟，以分析流体流动和固体本构模型对所得岩土材料响应的影响。本文的首要目标是更好地理解横向各向同性裂隙岩中的耦合固体变形-流体流动。