Prediction of Cell Pressure Error Utilizing GEP Procedure (A case study: Alborz embankment dam, Mazandaran, Iran)

Determination of stress in earthfill dams is one of the most important parameters in dam safety studies. Stress monitoring can be done using total pressure cells which are typically installed during construction. The cell is installed with its sensitive surface in direct contact with the soil to measure total stress of soil and in combination with piezometers to measure pore-water pressure acting in the soil mass. Total pressure cells needs to be installed with care to get reasonable measurements. However، measurements are often incompatible with the theoretical predictions such that pressure cell results usually have some inaccuracies. There are several parameters effecting pressure cell errors however in the present paper it is only focused on the height of embankment and the duration of dam construction. For this purpose a case study، namely Alborz embankment dam located in north part of Iran has been considered. It is an earth dam with clay core with a height of 78 m. Using the monitoring data and considering the effect of embankment height and construction period parameters، a model has been presented to predict the pressure cells error with Gene Expression Programming (GEP) procedure by GeneXProTools 4. 0 software. The computed coefficient of correlation (R2) for the proposed model is 0. 98 showing a good agreement with the monitoring data. The obtained results indicate that the ratio of height difference to time difference for Alborz dam has a significant role in dam pressure cells errors.