摘要
采用椰壳纤维联合微生物诱导碳酸钙沉积(MICP)技术对南水北调中线工程南阳段的膨胀土进行试验改良,对素土、纤维土、MICP土以及椰壳纤维-MICP复合改良土开展无荷膨胀率试验和有荷膨胀率试验,研究改良前后膨胀土无荷膨胀率、有荷膨胀率随纤维掺量的变化规律,并对比分析单一改良方式和复合改良方式下纤维掺量对膨胀土膨胀特性的影响,最后通过电镜扫描试验,观察土样微观结构,揭示纤维-MICP复合改良膨胀土特性的内在机理。结果表明:单掺椰壳纤维和MICP技术改良均可抑制膨胀土的膨胀性能,而椰壳纤维-MICP复合改良土的改良效果最明显,且随着纤维掺量的增加,纤维土和复合改良土的无荷膨胀率和有荷膨胀率呈现出先减后增的趋势,纤维最佳掺量为0.5%,电镜扫描试验显示椰壳纤维可发挥桥联的作用以增强MICP膨胀土的改良效果。
The coir fiber combined with MICP technology was used to improve the expansive soil in Nanyang section of the Middle Route of South-to-North Water Transfer Project.The unloaded expansion rate test and loaded expansion rate test were carried out on plain soil,fiber soil,MICP soil and coconut shell fiber-MICP composite improved soil,and the changes of unloaded expansion rate and loaded expansion rate of expansive soil with fiber content before and after improvement were studied.The effects of fiber content on the expansion characteristics of expansive soil under single improvement mode and composite improvement mode are compared and analyzed.Finally,through scanning electron microscopy,the microscopic structure of the soil sample was observed to reveal the underlying mechanism of the fiber-MICP composite-enhanced swelling soil properties.The results show that both coconut shell fiber and MICP technology can inhibit the expansive property of expansive soil,and the improvement effect of coconut shell fiber-MICP composite improved soil is the most obvious.With the increase of fiber content,the unloaded expansion rate and loaded expansion rate of fiber soil and composite improved soil show a trend of first decreasing and then increasing,and 0.5%is the best fiber content.Scanning electron microscopy experiments revealed that coconut fiber can act as a bridge to enhance the improvement effect of MICP-treated expansive soils.
作者
王钰珊
袁童
雷学文
WANG Yushan;YUAN Tong;LEI Xuewen(School of Urban Construction,Wuhan University of Science and Technology,Wuhan,Hubei,430065,China;China Construction 8th Bureau Shanghai Branch 5th Branch,Shanghai 200120,China)
出处
《水利与建筑工程学报》
2024年第5期67-71,81,共6页
Journal of Water Resources and Architectural Engineering
基金
国家自然科学基金面上项目(42372338,41877267)。
关键词
膨胀土
椰壳纤维
微生物诱导碳酸钙沉积(MICP)
复合改良
膨胀率
微观结构
expansive soil
coir fiber
microbial induced calcium carbonate precipitation(MICP)
compound improvement
expansion rate
microstructure
