CAS-1模拟月壤动剪切模量与阻尼比的试验研究

针对中国科学院地球化学研究所与国家天文台合作研制成功的CAS-1模拟月壤（国家标准试样），利用GDS共振柱试验仪对模拟月壤开展动力学参数的试验研究，分析了不同孔隙比、不同围压对动剪切模量G及剪应变 的影响规律。试验结果表明，在应力水平很低、孔隙比较大的真实月面环境条件下，动剪切模量G较小，阻尼比 较大，且随着动剪应变 的增大，动剪切模量快速减小，阻尼比急剧增大。采用Hardin-Drnevich模型，得到了不同孔隙比、不同围压下归一化动剪模量G/Gmax与归一化阻尼比 / 随 变化的平均拟合曲线，探讨了最大动剪切模量Gmax、最大阻尼比 和参考剪应变 等动参数与应力水平 的相关关系式，并据此给出了月壤钻取采样深度（0～3 m）内Gmax、 和 的值域区间以及各剪应变对应的G/Gmax和 的推荐值。

Experimental study of dynamic shear modulus and damping ratio of CAS-1 lunar soil simulant

Through the dynamic tests on the CAS-1 lunar soil simulant (national standard sample) which is developed by the Institute of Geochemistry and the National Astronomical Observatories, Chinese Academy of Sciences with the GDS resonant column test instrument, the effect of the different void ratios and the different confining pressures on the dynamic shear modulus G and the damping ratio ? is analyzed. The test results show that, the dynamic shear modulus G is smaller as well as the damping ratio ? is larger, and dynamic shear modulus decreases rapidly as well as damping ratio increases sharply with the increase of shear strain in the real lunar surface environmental conditions with low stress level and large void ratio. By using the Hardin-Drnevich model, the average fitting curve of G/Gmax and ? /? max with the change of the dynamic shear strain ? under different void ratios and different confining pressures are obtained; and the correlation formulas between dynamic parameters of the maximum dynamic shear modulus Gmax, the maximum damping ratio ? max, the reference shear strain ? r and the stress level ? are discussed. Accordingly, the range intervals of Gmax, ? max, ? r within the drill sampling depth (0-3 m) of the lunar soil as well as the recommended values of G/Gmax and ? corresponding to each of the shear strain are presented.