微生物固化砂柱效果电阻率评价研究

Cementation effect evaluation of MICP sand solidification via electrical resistivity

目前尚没有简便可行的方法对现场微生物固化效果进行评价,因此,提出采用便捷无损的电阻率法评价砂土的固化效果。首先对微生物固化砂柱的电阻率与孔隙率、含水率和碳酸钙含量的关系进行研究,然后研究了电阻率和无侧限抗压强度的关系,并提出综合参数N表示固化砂柱的孔隙率、含水率和碳酸钙含量,研究综合参数与固化砂柱电阻率和无侧限抗压强度的关系,从而提出微生物固化砂柱的电阻率模型。结果表明固化砂柱电阻率随着孔隙率的增加而增大,随含水率的增加而减小,随碳酸钙含量的增加近似线性减小。同时固化砂柱的电阻率与砂柱的相关性质存在较好的关联性。电阻率法是一种有效的微生物固化砂柱效果评价方法,可用在实际MICP技术的现场应用中。

There is no simple and feasible method to evaluate the on-site cementation effect of microbially induced calcium carbonate precipitation(MICP). Therefore, this study uses a convenient and non-destructive electrical resistivity method to evaluate the cementation effect of MICP sand solidification. First, the relationships of resistivity of MICP-solidified sand columns and porosity, water content, and calcium carbonate(CaCO3) content are studied. The relationship between the resistivity and the unconfined compressive strength of the solidified sand column is then studied. The comprehensive parameter is proposed to represent the porosity, water content and CaCO3 content of the solidified sand column, and the relationship between the comprehensive parameter and the resistivity or strengths is studied. Finally, a resistivity model for sand column solidified by MICP is proposed. The results show that the electrical resistivity increases with the increasing porosity, and it decreases with the increasing water content and also decreases approximately linearly with the increasing CaCO3 content. The electrical resistivity also has a good correlation with its related properties. The results demonstrate that the electrical resistivity method is an effective method to evaluate the cementation effect of MICP sand solidification, which can be used in the field application.