微生物加固路基强度及稳定性

微生物诱导沉积碳酸钙沉积技术(MICP,Microbially Induced Calcite Precipitation)是利用岩土层中的细菌微生物,在人为诱导作用下,生成具有胶结作用的碳酸盐沉淀,附着于岩土层间隙内,用于改善岩土层的强度,增强地基稳定性。利用MICP技术加固福建标准砂,进行不同围压下的三轴试验,结果表明,标准砂加固前后黏聚力的提高值为60.1kPa。利用Plaxis软件模拟高速公路路基加固技术,通过MICP诱导碳酸钙沉淀技术对高速公路路基加固,改变岩土体基本性能,利用强度折减法模拟在MICP技术加固前后路基的强度及稳定性变化,稳定性系数由1.096增大为1.827,高速公路路基经过MICP加固后,稳定性大大提高,边坡破坏面由坡脚移动至坡面。

Strength and stability of embankment foundation strengthened by MICP

Microbially Induced Calcite Precipitation (MICP) is a kind of novel biomineralization technique that utilizes natural bacteria isolated from farm land to generate calcite in the pore of soils or rock fracture. This technique could increase both the strength and stability of soil foundation. In this paper, Fujian standard sand was used to process a series of MICP experiments and the mechanical properties were also evaluated by static triaxial test under different confining pressures. It was found that the cohesion of sands improved by 60.1kPa after the MICP treatment. Then, Plaxis was also used to simulate the improvement of soil foundation treated by MICP technique. The improvement of both strength and stability in the embankment of expressway were measured by Shear Strength Reduction Methods. Result shows that MICP technique reinforced the mechanical property of soil foundation, and the slope stability factor was improved from 1.096 to 1.827 after treatment. The stability of expressway embankment improved significantly. Meanwhile, the ultimate slope slip surfaces moved from slope foot to slope surface.