Permeation grouting for remediation of dam cores

Abstract

Grouting methods are known to effectively remediate the dam foundation or the abutment. However, remediation grouting of the deteriorated embankment earth-core itself has rarely been performed or studied. In this study, low-pressure permeation grouting is adopted to remediate the deteriorated central core layers of five aging dams. Technical features of each dam's deterioration are described, such as sinkholes, slope failures, fluidized clay cores, and wet zones on the downstream surface induced by excessive seepage. This study suggests several empirical standards for the application of permeation grouting to the improvement of core permeability, including grout mix, injection period per stage, injection rate, and maximum fluid pressure to prevent hydraulic fracturing. The results of this empirical case study can be applied to effectively remediate degraded dam embankment cores to decrease their permeability and minimize the risk of hydraulic fracturing, without requiring a reduction in the reservoir water level.