Effect of Soil and Grouting Parameters on the Effectiveness of Compaction Grouting

Despite its many applications, compaction grouting has been suffering from the minimal empirical guidelines to predict the treatment effectiveness. This paper discusses the effects of soil parameters, soil compressibility, replacement ratio and injection sequence on the groutability and effectiveness of compaction grouting, through analyses of the results of a field test conducted under the old taxiway of Tokyo International Airport. The test consisted of eighty-seven compaction grout piles injected in three cases of different spacings, pile diameters and grouting procedures. Based on the analyses presented, unique relationships between the groutability, of compaction grouting and the soil parameters are identified. Also, empirical correlations for estimating the treatment effectiveness, based on the initial soil properties, are presented. Another finding is that the injection sequence may be controlled to provide confining action for the subsequence injections. The confined injections can effectively improve the highly compressible soils much more than the unconfined ones. In addition, it is recommended to avoid the condition, beyond which particle crushing becomes the dominant mechanism of deformation.