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为研究粉砂在不同冻融循环下的应力-应变关系特性,进行了粉砂土的不固结不排水三轴剪切试验,试验结果表明:在围压较低时,未冻融及经历较少次冻融循环的粉砂表现出一定的软化性,但软化程度较弱;而经历一定次数的冻融循环后,其逐渐由弱软化型转化成硬化型;在围压较高时,未冻融及冻融以后的粉砂都表现出应变硬化的特征,其应力-应变关系曲线为典型的双曲线。基于Konder双曲线模型,概述了土体应力-应变关系中常见的几种归一化因子及相应的归一化条件。提出了针对冻融循环下粉砂土的应力-应变关系的归一化因子,并给出了相应的归一化条件。基于新的归一化因子,建立了粉砂土在不同围压、不同冻融循环次数下的应力-应变特性的归一化方程,并对应力-应变曲线进行预测,其试验值与拟合值较为接近,预测效果较好。
In order to study the stress-strain relationship of silt under different freeze-thaw cycles, unconsolidated and undrained triaxial shear tests of silt sand were carried out. The results show that when the confining pressure is low, Less secondary freeze-thaw cycles of silt showed a certain degree of softening, but the degree of softening is weak; and after a certain number of freeze-thaw cycles, it gradually transformed from weak softening into hardened; at higher confining pressure, The silt that has not been frozen and thawed and frozen and thawed shows the characteristics of strain hardening. The stress-strain curve is a typical hyperbola. Based on the Konder hyperbola model, several common normalization factors and corresponding normalization conditions in soil stress-strain relationship are summarized. The normalization factor for the stress-strain relationship of silt sand under freezing-thawing cycles is proposed and the corresponding normalization conditions are given. Based on the new normalization factor, the normalized equation of the stress-strain behavior of silty sand under different confining pressure and freeze-thaw cycles is established and the stress-strain curve is predicted. The experimental values and fitting The value is closer, the prediction effect is better.