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投稿时间：2020-03-13 修订日期：2020-11-20
投稿时间：2020-03-13 修订日期：2020-11-20
中文摘要: 基于椭圆-抛物线弹塑性本构模型，研究了干湿循环条件下石灰粉煤灰改良膨胀土的双屈服面弹塑性应力-应变本构关系。首先，通过一系列三轴固结排水剪切试验，分别得到不同干湿循环次数下石灰粉煤灰改良膨胀土的偏应力q与轴向应变ε1、剪应变εs，以及轴向应变ε1与体应变εv的试验曲线；然后，根据三轴试验结果拟合本构模型中的各参数与干湿循环次数之间的关系表达式；最后，引入考虑干湿循环次数的因子，建立考虑干湿循环的双屈服面弹塑性本构模型。研究表明：1）干湿循环作用下，偏应力q与轴向应变ε1关系表现为应变硬化，与体应变εv表现为应变剪缩；q-ε1、q-εs试验曲线都呈现出近似双曲线特征。2）干湿循环作用下，土体的偏应力q不断减小，体应变εv不断增大；干湿循环作用显著降低了石灰粉煤灰改良膨胀土体的抗剪切、抗压缩能力。3）体积屈服面、剪切屈服面在p-q平面上分别为椭圆、抛物线。干湿循环作用下，体积屈服面不断向原点靠近，剪切屈服面不断向p轴靠近；前9次干湿循环作用的影响较为显著，之后屈服面的变化趋于稳定。4）通过引入考虑干湿循环次数的因子所建立的双屈服面本构模型，可定量反映干湿循环作用对石灰粉煤灰改良膨胀土应力-应变关系的影响，以及双屈服面演化过程。该双屈服面本构模型的应力-应变预测值与试验值吻合度较高。
中文关键词: 石灰粉煤灰改良膨胀土 干湿循环 椭圆-抛物线本构模型 双屈服面应力-应变关系
Abstract:The elasto-plastic stress-strain constitutive relation with double yield surfaces of expansive soil improved by lime and flyash was studied based on the ellipse-parabola constitutive model. Firstly, a series of the triaxial consolidated drained shear tests of the expansive soil improved by lime and flyash under wetting-drying cycles were conducted to obtain the test curves of deviatoric stress q and axial strain ε1, shear strain εs, and the test curves of bulk strain εv and axial strain ε1, respectively. Secondly, the expressions between the parameters of the ellipse-parabola constitutive model and wetting-drying cycles were fitted based on the triaxial test results. Finally, a modified ellipse-parabola constitutive model which can reflect the effect of wetting-drying cycles was proposed by introducing the factors of wetting-drying cycles. The study obtained conclusions as follows: 1) The stress-strain relationships between q and ε1 were strain hardening, and the relationships between q and εv were shrinkage under wetting-drying cycles, and the test curves of q-ε1、q-εs were hyperbola, respectively. 2) The deviatoric stress q decreased and the bulk strain εv increased under the wetting-drying cycles. The effect under wetting-drying cycles reduced the resistance of shear and compression of expansive soil treated by lime and flyash significantly. 3) The bulk yield surface was ellipse shape and the shear yield surface was parabola shape in the p-q stress plane. The bulk yield surface shrunk gradually to the origin of coordinates, and the shear yield surface degraded gradually to p coordinate in p-q stress plane, respectively. The effects of the first 9 wetting-drying cycles on the double yield surfaces were more obvious, and then the changes of double yield surfaces with wetting-drying cycles decreased gradually. 4) The constitutive model with double yield surfaces introduced the factors of wetting-drying cycles could quantitatively reflect the influences of wetting-drying cycles on the stress-strain relation of expansive soil improved by lime and flyash, and the evolutions of ellipse-parabola double yield surfaces. The proposed stress-strain constitutive equation could well predict the stress-strain relationship of expansive soil improved by lime and flyash under wetting-drying cycles.
keywords: expansive soil improved by lime and flyash wetting-drying cycle ellipse-parabola constitutive model stress-strain relation with double yield surfaces
文章编号：202000141 中图分类号：TU411 文献标志码：
基金项目:国家国际科技合作专项（2014DFA53120）；湖南省教育厅课题（20c1682）
作者简介:第一作者：邓云叶(1975-),女,副教授.研究方向:国土空间规划与生态建筑.E-mail:125586886@qq.com
引用文本：
邓云叶,文畅平.干湿循环下石灰粉煤灰改良膨胀土的双屈服面本构关系[J].工程科学与技术,2021,53(2):75-83.
DENG Yunye,WEN Changping.Constitutive Relation with Double Yield Surfaces of Expansive Soil Improved by Lime and Flyash Subjected to Wetting-drying Cycles[J].Advanced Engineering Sciences,2021,53(2):75-83.
引用文本：
邓云叶,文畅平.干湿循环下石灰粉煤灰改良膨胀土的双屈服面本构关系[J].工程科学与技术,2021,53(2):75-83.
DENG Yunye,WEN Changping.Constitutive Relation with Double Yield Surfaces of Expansive Soil Improved by Lime and Flyash Subjected to Wetting-drying Cycles[J].Advanced Engineering Sciences,2021,53(2):75-83.