The aim of this study is to investigate the possibility of predicting the yield curves of sandstones considering only a few key mechanical parameters, and more importantly microstructural properties. Porous rocks are modeled as a set of 2D circular grains subjected to radial and axial stresses that reflect the external forces applied on the material. The contact between individual grains define local planes. The sample is assumed to yield at the inception of nonlinear response on one of these planes, when local stresses reach either shear, tensile, or compressive limit values. A Mohr–Coulomb criterion is considered, with a tensile cutoff and a limitation on the maximum allowable shear stress. The parameters of the developed yield equations are then divided into two groups. The first category relates to the microstructure of the material: porosity, grain radius, intergranular contacts radius, and intensification factor. The second category contains a set of four mechanical properties: the cohesion, the friction angle, the maximum shear, and the compressive limit. While the first set differs from one sandstone to another, the second one is assumed to be the same for all sandstones showing similar mineral compositions. The experimental data for five sandstones, Berea, Boise, Darley Dale, Diemelstadt, and Rothbach, are gathered from the literature. The mechanical parameters are calculated based on Rothbach sandstone experimental data. Satisfactory predictions of the yield limits for the remaining sandstones are obtained from their microstructural characteristics.

中文翻译：

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从机械和微观结构特性预测砂岩的产量范围


本研究的目的是研究仅考虑几个关键力学参数，更重要的是微观结构特性来预测砂岩屈服曲线的可能性。多孔岩石被建模为一组受到径向和轴向应力的二维圆形颗粒，这些应力反映了施加在材料上的外力。各个颗粒之间的接触限定了局部平面。当局部应力达到剪切、拉伸或压缩极限值时，假设样品在这些平面之一上的非线性响应开始时屈服。考虑莫尔-库仑准则，具有拉伸截止和最大允许剪切应力的限制。然后将所开发的产量方程的参数分为两组。第一类与材料的微观结构有关：孔隙率、晶粒半径、晶间接触半径和强化因子。第二类包含一组四个机械属性：内聚力、摩擦角、最大剪切力和压缩极限。虽然第一组砂岩与另一种砂岩不同，但对于显示相似矿物成分的所有砂岩，第二组被认为是相同的。五种砂岩（Berea、Boise、Darley Dale、Diemelstadt 和 Rothbach）的实验数据来自文献。力学参数是根据Rothbach砂岩实验数据计算的。根据剩余砂岩的微观结构特征，对它们的屈服极限进行了令人满意的预测。