铁道科学与工程学报2025，Vol.22Issue(2)：664-676,13.DOI:10.19713/j.cnki.43-1423/u.T20240548
脱硫灰改良膨胀土裂隙发育及演化机理
The development and evolution mechanism of cracks improved by desulfurization ash in expansive soil
摘要
Abstract
In order to better explore the inhibition effect and mechanism of desulfurization ash on the crack development of expansive subgrade soils under dry-wet cycle conditions.By taking the expansive soil in the new District of Handan City,Jinan,China as the research object,the dry-wet cycle test was carried out on the plain expansive soil and the desulfurization ash improved soil,respectively.The CIAS software was used to binarize the crack images,and the development law of expansive soil cracks with different desulfurization ash contents was analyzed.The hydrogen ion concentration index,X-ray diffraction analysis,and Fourier infrared spectroscopy analysis were used to explore the changes of montmorillonite interlayer ions and crystal structure in the desulfurization ash improved expansive soil,and the mechanism of desulfurization ash inhibiting expansive soil cracks was summarized.The results show that when the added amount of desulfurization ash reaches 2.5%,the interlayer ions of montmorillonite in expansive soil are basically homogenized,all of them are filled with Ca2+,the fracture rate of expansive soil is obviously reduced,and the integrity is enhanced.When the added amount of desulfurization ash reaches 5%,there is almost no obvious fracture development in expansive soil.The content of desulfurization ash in expansive soil is negatively correlated with the crack rate,total crack length,average crack width and fractal dimension of expansive soil.The desulfurization ash can effectively inhibit the development of cracks in expansive soil.The mechanism of crack inhibition is that Ca2+ions in the desulfurization ash enter the interlayer of montmorillonite and replace the original Na+and H+in the interlayer,so that the ions in the interlayer of montmorillonite are homogenized and simplified,and the crystal structure of montmorillonite is changed,thus improving the characteristics of water swelling and water loss shrinkage of expansive soil.In addition,Ca(OH)2 in the desulfurization ash reacts with SiO2-3 and AlO3-3 in the expansive soil to form C-S-H gel and C-A-H gel,which fills the pores of the expansive soil.CaSO3,montmorillonite wafers and clay particles in the desulfurization ash adsorb each other,making the soil particles closer and inhibiting the development of cracks.The research results provide a reference for the design and construction of expansive soil subgrade.关键词
膨胀土/干湿循环/脱硫灰/裂隙发育/裂隙扩展机理Key words
expansive soil/dry-wet cycle/desulfurized ash/cracks development/fracture propagation mechanism分类
建筑与水利引用本文复制引用
徐嘉祥,赵海陆,徐博会,李冲,霍婷,崔贺宇,刘世明,赵存良..脱硫灰改良膨胀土裂隙发育及演化机理[J].铁道科学与工程学报,2025,22(2):664-676,13.基金项目
河北省教育厅基础研究重点培育专项(JZX2023010) （JZX2023010）
河北省重点研发计划项目(22374204D) （22374204D）
