Compaction Quality Control in Granular Shell of Earth Dam

The current procedure for controlling the quality of compaction in the granular shell of an earth dam is to compare the in situ density with the respective maximum laboratory density. This can be tedious on a routine basis during construction. A simple method is described here that does not replace but can readily enrich the results of the current procedure. It consists of taking readings at specified points on the settlements induced by the vibratory roller each time it goes over those points. The induced-settlement readings, correlated with the current results, provide additional data for controlling the attained in situ compaction. They are recorded and evaluated in two distinct forms: (1) the independent; and (2) the cumulative. In the first form, each reading starts fresh from zero, and in the second it is added successively to each new pass of the roller. Readings in the first form are seen primarily as point samples for quality control of compaction. Readings in the second describe the orbit traced by the settlements under repetitive dynamic loading. Finally, 630 results from a specific case are analyzed and commented on with reference to the two forms.