To study the mechanical properties of saturated sandstone, experiments were conducted under hydro-mechanical coupling on saturated sandstone. A damage constitutive model was established to describe the response of saturated sandstone under pore pressure, and its validity was verified using the results of the triaxial tests. The results indicate that the peak strength (σ p), effective peak strength (σ p′), residual strength (σ r), effective normal stress (σ n′), effective shear strength (τ n′), elasticity modulus (E), and rupture angle (θ) of sandstone are positively correlated with the confining pressure (σ 3) and negatively correlated with the pore pressure (P). Conversely, Poisson’s ratio (μ) exhibits an opposite relationship. The model parameters exhibit non-linear relationships with the confining pressure (σ 3), with the parameter m decreasing gradually as the confining pressure increases, and the parameter F 0 increasing with higher confining pressure (σ 3). Moreover, the pore pressure (P) and the confining pressure (σ 3) significantly affect the damage variables (D), with the stress value at the damage initiation point increasing with increasing confining pressure (σ 3), while the strain value at the damage initiation point decreasing with increasing pore pressure (P), indicating that pore pressure induces damage development in rocks.

中文翻译：

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水力耦合作用下砂岩强度特征及损伤本构模型


为了研究饱和砂岩的力学特性，对饱和砂岩进行了水力耦合试验。建立了描述饱和砂岩在孔隙压力下响应的损伤本构模型，并利用三轴试验结果验证了其有效性。结果表明：峰值强度（σ p）、有效峰值强度（σ p′）、残余强度（σ r）、有效正应力（σ n′）、有效剪切强度（τ n′）、弹性模量（E） ）、破裂角（θ）与围压（σ 3）呈正相关，与孔隙压力（P）呈负相关。相反，泊松比 (μ) 则呈现相反的关系。模型参数与围压(σ 3 )呈非线性关系，参数m随围压增大而逐渐减小，参数F 0 随围压(σ 3 )增大而增大。此外，孔隙压力（P）和围压（σ 3）显着影响损伤变量（D），损伤起始点处的应力值随着围压（σ 3）的增加而增加，而损伤起始点处的应变值则随着围压（σ 3）的增加而增加。损伤起始点随着孔隙压力（P）的增加而减小，表明孔隙压力诱发了岩石的损伤发展。