合肥膨胀土动弹性模量与阻尼比试验研究

以合肥膨胀土为研究对象，利用GDS真动三轴仪对土体进行循环动荷载试验，研究不同围压、固结应力比对土体动弹性模量及阻尼比的影响规律.试验结果表明，合肥膨胀土的骨干曲线可以由双曲线描述；在相同条件下，动弹性模量随着围压、固结应力比的增大而增大，随着动应变的增大先急剧减小后趋于平缓；动弹性模量的倒数与动应变呈良好的线性关系，最大动弹性模量随着围压的增大呈线性增大，给出考虑围压影响的最大动弹性模量回归方程；阻尼比随着围压、固结应力比的增大而减小，采用 Darendeli 模型及依据阻尼比与应变的经验关系，得到动模量比衰减模型及阻尼比模型；不同围压、固结应力比下阻尼比与动模量比的关系归一化后可以由修正Hardin-Drnevich公式描述.

Experimental study of dynamic elastic modulus and damping ratio of expansive soil in Hefei

A series of dynamic triaxial tests were conducted by GDS to analyze the influence of different confining pressures, consolidation ratios on the dynamic modulus and damping ratio of the soil by taking expansive soil in Hefei as the research object. The test results show that the stress-strain backbone curve can be described by hyperbolic function. The dynamic modulus of elasticity increases with the increase of confining pressure and consolidation stress ratio, and decreases sharply at first then tends to be flat with the increase of dynamic strain under the same conditions. The reciprocal of elastic modulus has a linear relationship with dynamic strain. The maximum modulus increases linearly with the increase of confining pressure. A regression model of maximum dynamic modulus and elasticity regression considering confining pressure was developed. Damping ratio decreases with the increase of confining pressure and consolidation stress ratio. An attenuation model of dynamic modulus ratio and a damping ratio model were established based on the Darendeli’s model and empirical relation between damping ratio and strain. The relationship between damping ratio and dynamic modulus ratio under different confining pressure and consolidation stress ratio after normalization processing can be described by the modified formula of Hardin-Drnevich.