冻融循环下粉砂土应力-应变归一化特性研究

发布时间：2018-03-11 06:30

本文选题：冻融循环　切入点：粉砂土　出处：《岩土力学》2015年12期 　论文类型：期刊论文

【摘要】：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。
[Abstract]:In order to study the stress-strain relationship of silty sand under different freezing and thawing cycles, the unconsolidated undrained triaxial shear test of silty sand is carried out. The experimental results show that when the confining pressure is low, The silty sand without freeze-thaw and with less freeze-thaw cycles shows a certain softening property, but the softening degree is weak, and after a certain number of freeze-thaw cycles, it gradually changes from weakly softened type to hardened type, and when the confining pressure is high, After freeze-thaw and freeze-thaw, silt shows the characteristic of strain hardening, and its stress-strain relation curve is typical hyperbolic. Based on Konder hyperbolic model, Several kinds of normalized factors and corresponding normalization conditions in the stress-strain relationship of soil are summarized. A normalized factor for the stress-strain relationship of silty sand under freeze-thaw cycle is proposed. Based on the new normalized factors, the normalized equations of stress-strain characteristics of silty sand under different confining pressures and different freeze-thaw cycles are established, and the stress-strain curves are predicted. The experimental value is close to the fitting value and the prediction effect is better.
【作者单位】：北京交通大学土木建筑工程学院;青海省交通科学研究院多年冻土地区公路建设与养护技术交通行业重点实验室青海研究观测基地;
【基金】：国家重点基础研究发展计划(973计划)(No.2012CB026104) 国家自然科学基金(No.51378057,No.41371081)~~
【分类号】：TU445

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