Statistical Quality Control at Kastraki Earth Dam

Quality control methodology and results obtained for soil are presented and examined. Sampling for acceptance in this project was purposive. Quality control results thus obtained have been compiled and presented statistically, and their usefulness and limitations are examined. In addition to the simple quality control chart which was kept from day to day during the production period, the following graphics were found valuable in reporting results and rating performance for this type of sampling: (1) Rejection charts (for performance over periods of about 1 week or more); and (2) frequency diagrams in couples (for whole parts of the project). The rejection chart described in this paper was proven to be a simple and informative presentation to study the behavior of defects and take field decisions on sampling. Frequency diagrams compiled and evaluated in couples (with defects and induced retests alternatively excluded and compared) gave a tool for assessing the quality and process control that was attained.