Study on Microstructure of Cemented Organic Soil in Dianchi Lake, China
Study on Microstructure of Cemented Organic Soil in Dianchi Lake, China
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DOI：
10.3390/app13031825
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发表时间：
2023-01
期刊：
影响因子：
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通讯作者：
Siyang Huang;Jing Cao;Yunfei Song;Z. Song;Hong Liu;Lin Tian
中科院分区：
文献类型：
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作者：
Siyang Huang;Jing Cao;Yunfei Song;Z. Song;Hong Liu;Lin Tian
滇池地区有机土壤中含有大量腐植酸，腐植酸对胶结土的影响备受关注。本研究根据滇池土壤的实际HA含量制备试验土，并加入水泥制备样品。对试样进行了无侧限抗压强度（UCS）、扫描电镜（SEM）、能谱分析（EDS）和x射线衍射（XRD）测试。研究了胶结有机土的强度发展和微观结构变化。结果表明：(1)水泥土强度随HA含量的增加而减小，随水泥掺量的增加而增大；(2) SEM和EDS测试表明，随着HA含量的增加，土壤颗粒之间的连接逐渐由表面-表面转变为点-表面、点-边缘或点-点连接。胶结土内部存在较大的架空结构，其完整性随着HA含量的增加而减弱。而水泥土孔隙中存在Ca、Si、Al等元素，说明水泥土水化产物在土粒之间发生了胶结。XRD测试表明，随着HA含量的增加，水泥土中水化产物的衍射峰强度逐渐减小。(3)一般情况下，HA会逐渐破坏水泥土的完整性，降低水泥土的强度。当HA含量大于15%时，HA对强度的影响更为突出。而增加水泥掺量可有效减弱HA对水泥土强度的负面影响。当水泥掺量在15% ~ 25%之间时，可有效提高高HA含量水泥土的强度。然而，这种做法不利于环境的保护。
The organic soil in the Dianchi Lake area contains much humic acid (HA), and the impact of HA on cemented soil has attracted much attention. In this study, test soil is prepared based on the actual HA content of the soil in Dianchi Lake, and cement is added to prepare samples. Unconfined compressive strength (UCS), scanning electron microscopy (SEM), energy-dispersive analysis (EDS), and X-ray diffraction (XRD) tests are conducted on the samples. The strength development and microstructure changes of cemented organic soil are studied. The results show that (1) cemented soil strength decreases with the increase in HA content and increases with the cement mixing ratio; (2) SEM and EDS tests show that with the increase in HA content, the connection between soil particles gradually changed from surface–surface to point–surface, point–edge, or point–point connection. A large overhead structure is inside the cemented soil, and its integrity weakens with increased HA content. However, elements such as Ca, Si, and Al exist in the pores of cemented soil, indicating that cement hydration products are cemented between soil particles. XRD testing shows that with the increase in HA content, the intensity of the diffraction peaks of hydration products in cemented soil gradually decrease. (3) In general, HA will gradually deteriorate the integrity of cemented soil and reduce its strength. When the HA content is more than 15%, the effect of HA on strength is more prominent. However, increasing the cement mixing ratio can effectively weaken HA’s negative effect on cemented soil’s strength. When the cement mixing ratio is between 15% and 25%, the strength of cemented soil with high HA content can be effectively increased. However, this approach is not conducive to the protection of the environment.