Multi-resistivity survey method to confirm the quality of grouting injection Available to Purchase

Grouting is widely used to reinforce soft strata in reinforcement engineering projects, but few methods to confirm the quality of grout injection are available. Here, a multi-resistivity survey method is proposed to evaluate the grout reinforcement effect after grouting. Firstly, coordinate transformation equations are established, and electrical resistivity tomography (ERT), cross-hole ERT and principal component analysis (PCA) methods are applied to obtain three-dimensional (3D) resistivity imaging. Numerical analysis using three types of synthetic grouting models was performed to study the grouting resistivity change and verify the feasibility of the method. A field application was also conducted to show the use of the method. The results showed the following. Grouting increased the resistivity of the reinforced area. Both ERT and cross-hole ERT methods can reflect resistivity changes, and PCA is useful to obtain more precise resistivity imaging. The farther away from the grouting opening, the less grout was found and, in the same formation, the deeper the depth, the shorter the grout diffusion distance. To improve the grouting reinforcement effect, grouting boreholes should be encrypted; their respective grouting reinforcement zones would then intersect, forming a collaborative grouting reinforcement area.