The mechanical behavior of the sandy facies of Opalinus Clay (OPA) was investigated in 42 triaxial tests performed on dry samples at unconsolidated, undrained conditions at confining pressures (p_c) of 50–100 MPa, temperatures (T) between 25 and 200 °C and strain rates (\(\dot{\varepsilon }\)) of 1 × 10^–3–5 × 10^–6 s⁻¹. Using a Paterson-type deformation apparatus, samples oriented at 0°, 45° and 90° to bedding were deformed up to about 15% axial strain. Additionally, the influence of water content, drainage condition and pre-consolidation was investigated at fixed p_c–T conditions, using dry and re-saturated samples. Deformed samples display brittle to semi-brittle deformation behavior, characterized by cataclastic flow in quartz-rich sandy layers and granular flow in phyllosilicate-rich layers. Samples loaded parallel to bedding are less compliant compared to the other loading directions. With the exception of samples deformed 45° and 90° to bedding at p_c = 100 MPa, strain is localized in discrete shear zones. Compressive strength (σ_max) increases with increasing p_c, resulting in an internal friction coefficient of ≈ 0.31 for samples deformed at 45° and 90° to bedding, and ≈ 0.44 for samples deformed parallel to bedding. In contrast, pre-consolidation, drainage condition, T and \(\dot{\varepsilon }\) do not significantly affect deformation behavior of dried samples. However, σ_max and Young’s modulus (E) decrease substantially with increasing water saturation. Compared to the clay-rich shaly facies of OPA, sandy facies specimens display higher strength σ_max and Young’s modulus E at similar deformation conditions. Strength and Young’s modulus of samples deformed 90° and 45° to bedding are close to the iso-stress Reuss bound, suggesting a strong influence of weak clay-rich layers on the deformation behavior.

在不固结，不排水的条件下，于50–100 MPa的围压（p _c），温度（T）在25至200°之间，对干样品进行了42次三轴试验，研究了Opalinus粘土（OPA）砂岩相的力学行为。C和应变率（\（\ dot {\ varepsilon} \））为1×10 ^–3 –5×10 ^–6  s ^-1。使用Paterson型变形设备，将在0°，45°和90°定向为顺层的样品变形到大约15％的轴向应变。此外，在固定的p _c – T下研究了水含量，排水条件和预固结的影响。条件下，使用干燥和重新饱和的样品。变形后的样品表现出脆性到半脆性的变形行为，其特征是富含石英的砂质层中有碎裂流，富含页硅酸盐的层中有颗粒流。与其他装载方向相比，平行于床上用品装载的样品的顺应性较差。除了在p _c  = 100 MPa时变形为45°和90°变形为顺层的样品外，应变仅限于离散的剪切区域。抗压强度（σ_最大）随着增加p _Ç，导致≈0.31，在45°和90°到寝具变形样品的内部摩擦系数，以及用于平行于寝具变形样品≈0.44。相比之下，预固结，排水条件，T和\（\ dot {\ varepsilon} \）不会显着影响干燥样品的变形行为。然而，σ_最大和杨氏模量（ë）与水饱和度增加显着降低。相比于OPA丰富的粘土泥质岩，砂质岩标本显示较高的强度σ_最大和杨氏模量Ë在类似的变形条件。变形为90°和45°变形为顺层的样品的强度和杨氏模量接近于等应力的Reuss界限，表明弱的富粘土层对变形行为有很大影响。