微生物入渗注浆法加固非饱和砂土的研究

STUDY OF THE MICP INJECTION IN UNSATURATED SANDY SOILS

微生物诱导碳酸钙沉积(MICP)是一项新兴的地基处理技术。以往研究中,主要是把灌输至饱和砂土中;然而最近研究者发现:MICP工法的不同会影响CaCO3的沉积和与砂颗粒结合的位置及效果,从而影响样品的强度和均匀性。与饱和土样中的灌浆法不同,通过向砂土试样中渗入或灌入微生物浆液,然后通过扫描电子显微镜(SEM)和无侧限抗压强度试验来考查其性能。结果表明:入渗法处理非饱和土样(无侧限抗压强度平均值为(19.7±5.86)MPa)效果要比灌浆法处理饱和土样(无侧限抗压强度平均值为(15.1±5.73)MPa)要好。

Microbially induced carbonate precipitation （MICP） is a novel ground treatment solution. In the past, the solution was always injected into saturated sandy soil; however recently, researchers have discovered that the effect and position of the CaCO3 bonding the sand would be different changing with different injection method, and they had great impact in the strength and homogeneity of treated samples. Reverse injection saturated method and unsaturated percolation method were compared. Scanning electron microscope （SEM） and unconfined compression strength （UCS） tests were used to estimate the behavior of the samples. The results showed that the samples treated with the unsaturated percolation method had superior quality（ an average UCS of （19.7 ± 5.86） MPa） than the ones treated with the reverse injection saturated method（ （15. 1 ± 5.73 ）MPa）.