Grouting is a geotechnical process involving, for example, injection of a cement sand and water mixture or chemical resins into the ground to improve the strength and to decrease the permeability of rocks and soils. The efficiency of grouting operations is generally assessed by carrying out permeability and loading tests. Additionally, the comparison of the seismic field velocities of a rock mass obtained before and after the grout infection operation can give a qualitative indication of the effectiveness of grouting. However, for a quantitative assessment of grouting efficiency, more complex analysis of the rock mass seismic velocity is required.