Strain rate is one of the main factors affecting the properties of rock masses. The effect of strain rate on performance of gas storage in aquifer is investigated combining laboratory tests and constitutive and numerical models. Triaxial tests on sandstone specimens at different strain rates were carried out and the effect of strain rate on mechanical properties of sandstones was investigated. The results showed that the peak strength, axial strain, elastic modulus, Poisson’s ratio, cohesion and internal friction angle of sandstone specimens increased with strain rate. In addition, the elastic–viscoplastic properties of sandstones have been analyzed. It indicated that the deflection angle in the viscoplastic flow direction was increased with strain rate and viscoplastic volumetric strain grew faster than the viscoplastic deviator strain. A rate-dependent constitutive model was adopted and a method for solving the parameters of the constitutive model was determined based on test data. For the constitutive model, the elastic part is a linear elastic model, the plastic part is a linear Drucker–Prager model, and the viscous part is a power law constitutive function. The model and methodology for parameter determination were validated against the test data of sandstones. The results showed that the model selected in this study can well describe effects of strain rate on the mechanical properties of sandstones. The model and method have been applied in gas injection and production capacity assessment of a gas storage in aquifer and the strain rate of the formation was determined by gas injection pressure and time indirectly in simulation. The simulation results showed that the gas injection and production rate of gas storage in aquifer will increase significantly with the strain rate of formation in the same gas injection pressure or time. It also indicated that the gas production capacity will be greatly improved with the strain rate of formation.

应变率是影响岩体性质的主要因素之一。结合实验室试验、本构模型和数值模型，研究了应变率对含水层储气性能的影响。对砂岩试样在不同应变率下进行了三轴试验，研究了应变率对砂岩力学性能的影响。结果表明，砂岩试样的峰值强度、轴向应变、弹性模量、泊松比、内聚力和内摩擦角随应变速率的增加而增加。此外，还分析了砂岩的弹粘塑性特性。这表明粘塑性流动方向的偏转角随应变速率的增加而增加，并且粘塑性体积应变的增长速度快于粘塑性偏应变。采用速率相关的本构模型，并根据试验数据确定本构模型参数的求解方法。对于本构模型，弹性部分为线弹性模型，塑性部分为线性 Drucker-Prager 模型，粘性部分为幂律本构函数。针对砂岩的测试数据验证了参数确定的模型和方法。结果表明，本研究选择的模型能够很好地描述应变率对砂岩力学性质的影响。该模型和方法已应用于含水层储气库的注气和产能评估，模拟中通过注气压力和注气时间间接确定地层应变率。模拟结果表明，在相同的注气压力或注气时间下，随着地层应变率的增加，含水层中储气库的注气和产气量会显着增加。这也表明，随着地层应变率的提高，产气能力将大大提高。