黄泛区非饱和粉土动模量和阻尼比特性研究

Dynamic modulus and damping ratio characteristics of unsaturated silt in the Yellow River flood field

黄泛区粉土水敏感性强,力学性质独特,易受振动荷载的影响。本文通过循环三轴试验,研究固结围压和饱和度对黄泛区粉土动模量、阻尼比特性的影响。研究结果表明,黄泛区粉土骨干曲线符合双曲线关系;随动应变的增大,黄泛区粉土动弹性模量先急剧减小而后逐渐趋于稳定;随固结围压的增大和饱和度的减小,粉土动弹性模量逐渐增大,阻尼比则逐渐减小;二元线性方程可用于估算最大动弹性模量随固结围压和饱和度的变化规律,修正Hardin-Drnevich模型可较为准确预测黄泛区非饱和粉土的动弹性模量和阻尼比。本研究可为黄河流域工程建设提供理论支撑。

The silt in the Yellow River flood field exhibits strong water sensitivity and unique mechanical properties,which makes it vulnerable to vibration load.This study investigates the dynamic elastic modulus and damping ratio characteristics of the silt by considering the influence of confining pressure and saturation through dynamic triaxial tests.Test results indicate that the backbone curves of the silt are consistent with a typical hyperbolic relationship.The dynamic elastic modulus sharply decreases and eventually tends to stabilize with increasing dynamic strain.Furthermore,the dynamic elastic modulus gradually increases with an increment in confining pressure and decrement in saturation,while the damping ratio simultaneously decreases.A binary linear equation can conveniently estimate the dynamic elastic modulus at a small strain.Based on quantitative analyses,a modified Hardin-Drnevich model is preliminarily proposed to calculate the dynamic elastic modulus and damping ratio of the silt.This investigation supplies a theoretical reference for the engineering construction of the Yellow River basin.