High-porosity granular rocks are moisture-sensitive solids, in that their strength and deformability are modulated by the relative humidity of their environment. Here, a novel continuum breakage–damage framework is developed to characterize and simulate the inelasticity of cemented granular materials subjected to changes of relative humidity. A microstructural model is proposed to describe the evolution of the solid–fluid interfaces emerging from grain breakage and cement disintegration. The proposed thermodynamic framework links the microstructural model to the energy dissipation and macroscopic rate-dependence of sandstones. The performance of the model is assessed against experimental data for sandstones subjected to loading under both dry and wet conditions. It is shown that the proposed model can accurately predict the yielding and stress–strain response of sandstones by capturing the moisture-weakening effects. The simulations of the model indicate that the increase of moisture lowers the yield stress and reduces the brittleness of the post-yielding response of variably saturated cemented granular materials. It is shown that the rate of damage and breakage growth control the distortion of the yield surface. When inelasticity is dominated by damage, cement bonds are disintegrated and the yield surface shrinks, thus resulting into augmented brittleness. By contrast, and in agreement with experimental evidence, the response of lightly cemented granular solids is found to be dominated by the breakage of the skeletal grains. As a result, changes in relative humidity are predicted to be accompanied by hardening behavior.

高孔隙率粒状岩石是对水分敏感的固体，因为它们的强度和变形能力受环境相对湿度的调节。在这里，开发了一种新的连续断裂-损伤框架来表征和模拟胶结颗粒材料在相对湿度变化下的非弹性。提出了一个微观结构模型来描述因颗粒破碎和水泥崩解而出现的固-流体界面的演变。所提出的热力学框架将微观结构模型与砂岩能量耗散和宏观速率依赖性. 模型的性能是根据砂岩在干燥和潮湿条件下承受载荷的实验数据进行评估的。结果表明，所提出的模型可以通过捕捉水分弱化效应来准确预测砂岩的屈服和应力应变响应。模型的模拟表明，水分的增加降低了屈服应力，降低了变饱和胶结颗粒材料屈服后响应的脆性。结果表明，损伤率和断裂生长率控制着屈服面的变形。当非弹性以损伤为主时，水泥键解体，屈服面收缩，从而导致脆性增强。相比之下，与实验证据一致，发现轻胶结颗粒固体的响应主要是骨架颗粒的破坏。因此，预计相对湿度的变化将伴随着硬化行为。