Study of evaluating non-exceedance probability for dam foundation curtain-grouting quality management

Abstract

Curtain-grouting is necessary to improve hydraulic and dynamic properties for dam foundation stability. Adequate evaluation of grouting improvement is extremely important for its rational execution. Such evaluation is conducted in accordance with the non-exceedance probability for a target Lugeon value. Ordinarily, for the grouting area, the probability is calculated from Lugeon values of regular pattern holes and supplementary ones individually. The probability for regular pattern holes conducted equally in the area represents the overall grouting effectiveness. However, although the probability for the supplementary holes does not represent the effectiveness, it has been regarded in many cases as the criterion of effectiveness. A new rational process of evaluating the probability is provided herein: it synthesizes both holes. Additionally, a rational process is provided for the reduction of supplementary holes. These processes were demonstrated as useful for curtain-grouting quality management at a domestic dam construction site.