微生物胶结在防治堤坝破坏中的应用研究

Application of bio-cement in erosion control of levees

为防治漫顶引起侵蚀造成堤坝破坏,将微生物诱导碳酸钙沉淀即MICP技术应用于加固堤坝表层。通过向堤坝表层喷洒微生物细胞以及营养盐,最终在砂土孔隙中快速析出碳酸钙胶凝结晶,以改善堤坝表层砂的力学性能。首先,采用喷洒法处理堤坝表层;其次,对处理好的堤坝模型进行水槽试验,研究其抗侵蚀性;最后,对堤坝表层的试样进行强度与渗透试验。试验结果表明,采用MICP技术加固堤坝模型表层可有效提高其抗侵蚀力,防治由漫顶引起的堤坝破坏。对加固后的表层取样进行测试,结果表明:无侧限抗压强度可高达9MPa,渗透系数从4×10^(-4)m/s降低至7.2×10^(-7)m/s。试验说明,微生物胶结技术在加固堤坝表层方面具有潜在的工程实用价值和广阔的应用前景。

To mitigate the erosion problem due to overtopping, the MICP（microbial induced carbonate precipitation） treatment method was applied to the levee surface so that its resistance to erosion was improved. By spraying the bacterial cells and nutrient solutions into the surface sand of levee, the gelation of calcium carbonate can precipitate rapidly in the interspaces, improving the mechanical properties of levee surface sand. To this end, the spray method was first used to treat the surface layer of levee model, and then the flume test was carried out to evaluate the ability of the model against erosion. After the flumes test, the engineering properties of the soil in the model were examined using an unconfined compressive test and hydraulic conductivity test. The experimental results show that the engineering properties of the model soil has been greatly improved. The UCS（unconfined compressive strength） reaches up to 9 MPa. The hydraulic conductivity of the bio-treated sand taken from the levee model is reduced from the initial value of 4.0×10？4 to 7.2×10^7 m/s. In short, the bio-grouting technology has a potential to be used in practice with a broad application prospect in erosion control of levees.