Practical Aspects of Water Pressure Testing for Rock Grouting

Rock mass permeability testing has been performed to characterize rock formations since the early 20th century. It was further popularized by Maurice Lugeon (1933) after he defined a standard unit for quantifying the transmissive ability of rock discontinuities. As the dam and grouting industries developed and flourished in the latter half of the 20th century, more attention was devoted to better understanding water pressure testing and its application to rock grouting projects. Today, water pressure testing is a well-established practice and is one of many useful tools for characterizing rock formations. However, it seems the benefits of water testing may not be fully understood from a rock grouting perspective. In several recent grouting designs, the authors have observed that water pressure testing has been incorporated for the sole purpose of measuring the permeability of the untreated formation. Such a limited use of the test and results inhibits important evaluation of project quality and production efficiency. In the last two decades, the grouting industry has seemingly dedicated more effort toward technical interpretation of the water pressure test while not promoting its many practical and technical benefits. In this paper, the authors expound on numerous uses for water pressure testing which add to the overall value of a rock grouting program and advocate for increasing quality and production efficiency. To maintain such progress, geoprofessionals in these industries should maximize the application of available tools and continue promoting innovation in this dynamic field of work.