黄原胶生物聚合物固化红黏土力学行为及强化机制
Mechanical behavior and strengthening mechanism of red clay solidified by xanthan gum biopolymer
翁之宇 1俞缙 1邓永锋 2蔡燕燕 1王立娜3
作者信息
- 1. Fujian Research Center for Tunneling and Urban Underground Space Engineering,Huaqiao University,Xiamen 361021,China
- 2. Institute of Geotechnical Engineering,Southeast University,Nanjing 211189,China
- 3. College of Construction Engineering,Yunnan Agricultural University,Kunming 650201,China
- 折叠
摘要
红黏土不良的岩土特性会诱发工程病害,而大量使用水泥、石灰等传统无机固化材料处理红黏土会对生态环境造成不可逆的影响,有必要探索低环境影响材料用以提升红黏土的工程力学性能,经固化的红黏土既可充当工程材料运用,又满足绿色可持续发展需求.目前,黄原胶(XG)生物聚合物被视为一种极具挖掘潜力的环境友好型土壤稳定材料,具有优异的假塑性、安全性和稳定性等特性.本文为了系统地探究黄原胶生物聚合物对红黏土的固化效用及强化机制,在不同黄原胶掺量和养护龄期条件下,对固化后的红黏土开展了无侧限抗压强度试验、不固结不排水剪切试验、扫描电镜-能谱(SEM-EDS)及X射线衍射(XRD)测试.结果表明,在1.5%最佳掺量和28 d标养下,XG有效提升了红黏土的宏观力学性能,固化体的抗压强度和粘聚力分别提高了93.31%和79.47%;引入Duncan-Chang本构模型并进行修正,建立了适用于描述黄原胶生物聚合物固化红黏土应力-应变关系的数学模型,计算结果与试验结果一致性较好;黄原胶生物聚合物通过与红黏土和水分子之间的离子键作用,在固化体微观结构演化过程中产生显著的胶结和充填效应,最终形成致密的复合材料基体.
Abstract
To avoid engineering diseases induced by negative geotechnical properties of red clay and to positively reduce adverse impacts on ecological environments caused by employing lots of inorganic solidified material for treating the clays,it is essential to explore low-environmental impact material to improve engineering mechanical performances of the red clay.To date,xanthan gum(XG)biopolymer is regarded as a potentially eco-friendly material with excellent pseudo-plasticity,safety,and stability.Hence,unconfined compressive strength,unconsolidated undrained shear,scanning electron microscopy-energy dispersive spectroscopy,and X-ray diffraction tests were performed to study the solidification effects and strengthening mechanism of XG for red clay under varied additive contents and curing period.The results indicated the optimal XG content and curing ages to increase the macro-mechanics of red clay are 1.5%and 28 d,in which the compressive strength and cohesion are increased by 93.31%and 79.47%,respectively.Further,the mathematical model is established by modifying the Duncan-Chang constitutive model and used to describe the stress-strain relationship of XG-solidified red clay,presenting preferable consistency in the calculated and trial results.The strengthening mechanism is derived from the ionic bondings between XG and red clay,producing significant effects of cementing and filling to form compact composite matrices during the microstructural evolution process.
关键词
土壤固化/红黏土/黄原胶生物聚合物/力学行为/强化机制Key words
soil solidification/red clay/xanthan gum biopolymer/mechanical behavior/strengthening mechanism引用本文复制引用
基金项目
National Natural Science Foundation of China(52278351)
National Natural Science Foundation of China(51978292)
National Natural Science Foundation of China(52108346)
Science and Technology Planning Project of Fujian Province,China(2022Y0029)
出版年
2023
NETL
NSTL
维普
万方数据