Evaluation of the grout injectability and types of resistance to grout flow

From the injection tests different resistances to grout penetration were detected, created by the porous medium to the flow. The knowledge of these resistances is crucial to estimate the grout penetration in the internal voids. In contrast with literature, the injection tests show that Darcy's law and front resistance are not adequate to estimate the grout injection. Therefore, an additional resistance is introduced (resistance of suspension - Rs). This resistance, as well as the overall resistance to grout flow are reduced when the pre-wetting of the porous medium (before grout injection) is done. The performance of the grout injection performance was also analysed in the hardened state with ultrasonic tomography.