铁道科学与工程学报2025，Vol.22Issue(3)：1074-1086,13.DOI:10.19713/j.cnki.43-1423/u.T20240850
水玻璃-聚丙烯纤维改良膨胀土的强度及裂隙特性
Sodium silicate solution and polypropylene fiber modified expansive soil strength and crack characteristics
摘要
Abstract
To investigate the effectiveness of using sodium silicate-polypropylene fiber composite to improve expansive soil in subgrade engineering,expansive soil samples were mixed with varying mass ratios of sodium silicate(0.0%,0.5%,1%,1.5%,2.5%)and polypropylene fiber(0.0%,0.1%,0.2%,0.3%,0.4%,0.5%).The unconfined compressive strength tests,wet-dry cycle direct shear tests,fissure tests,and SEM(scanning electron microscope)microanalysis were conducted to study the strength and fissure characteristics of the modified expansive soil.IPP software was used to process fissure images,exploring the fissure development trend in the modified soil.The mechanisms of sodium silicate and polypropylene fiber in improving expansive soil were analyzed,focusing on their impact on soil strength and fissure characteristics.The results are as follows.Both sodium silicate and polypropylene fiber enhance the strength of expansive soil.When combined,the soil strength peaked,and fissure inhibition is optimal at a ratio of 1%sodium silicate and 0.4%polypropylene fiber.After 1 to 5 wet-dry cycles,the composite improved soil can exhibite significantly higher shear strength compared to untreated expansive soil,demonstrating enhanced resistance to wet-dry cycles.Furthermore,during the wet-dry cycles,untreated expansive soil can develope extensive fissures.Sodium silicate-modified soils show dense fissure development,dividing the soil into multiple sections.The composite-modified soil can exhibite less and slower fissure development.Quantitative analysis of the fissure area ratio,fissure number,average fissure width,and total fissure length,combined with observations of fissure morphology changes during different cycles and single drying processes,allowed for the prediction of fissure development trajectories.SEM image analysis and fissure development diagrams can elucidate the causes of fissure formation,revealing the internal mechanism of sodium silicate and polypropylene fiber in improving expansive soil.The intertwining of silicon gel adhesive films formed by polypropylene fiber and sodium silicate with soil particles can create a fiber-silicon gel adhesive system,increasing the inter-particle bonding strength and reducing pore connectivity,thus inhibiting fissure formation and propagation.These findings can provide a scientific basis for selecting and evaluating soil improvement techniques.关键词
膨胀土/水玻璃/聚丙烯纤维/干湿循环/裂隙发育Key words
expansive soil/sodium silicate solution/polypropylene fiber/wet-dry cycles/crack development分类
建筑与水利引用本文复制引用
肖桂元,王浩鹏,邓杰,刘星,杨帅..水玻璃-聚丙烯纤维改良膨胀土的强度及裂隙特性[J].铁道科学与工程学报,2025,22(3):1074-1086,13.基金项目
国家自然科学基金资助项目(52169022) （52169022）
