SELECTION OF TEST METHOD FOR QUALITY ASSURANCE OF GROUND IMPROVED BY PERMEABLE GROUTING METHOD

Abstract

 The unconfined compressive strength (UCS) of the sandy ground improved by the Permeable Grouting Method is usually set to about 100 kN/m² of the UCS. Since the strength reveals rather lower value than that of the clayey improved ground, it is concerned that the strength could be underestimated due to the disturbance of samples during sampling. To avoid the effect of disturbance, in-situ tests, as alternative methods, are proposed to use for estimating the unconfined compressive strength. However, in actual application, the conditions to select the method for quality assurance have not been clarified so far. In this study, an analysis on the UCS of core samples is carried out to study the conditions for selecting methods in quality assurance. The results show that the unconfined compression test using undisturbed samples is applicable to the evaluation of the improved ground with the gravel content of 15 % or less and the average particle size of 1 mm or less. In this case, it is noted that the specimen obtained from the sample with the sampling rate of 75 % or more should be used.