One of the most important issues in earth dams is the control rate of seepage from the foundation and dam bodies. Due to the site of the dams, to increase the creep length and reduce the seepage, there are several methods for sealing the reservoir of dams that construction of the cut-off wall under the clay core of the dams is one of the most effective methods. In this study, the seepage rate and pore water pressure of the Eyvashan earth dam, comparison of instrument results with the results of numerical analysis and, finally, the performance of the cut-off wall are investigated. According to the results of instrumental and numerical analysis, the maximum seepage rate in full reservoir conditions is equal to 831,604 m³/year. To fit the data of instrumentation and numerical analysis, multivariate regression was used and the coefficient of determination was used which R² = 0.9892 and R² = 0.9834, respectively, were obtained for seepage and pore water pressure. Very good agreement between the results of the observed data and the predicted data indicates the proper behavior of the dam in terms of pore water pressure. Also, due to the results of numerical simulation and instrumentation, the pore water pressure in the downstream part of the cut-off wall is suddenly dropped, which indicates the correct operation of the cut-off wall.

土坝中最重要的问题之一是基础和坝体的渗漏控制率。由于大坝的位置，为了增加蠕变长度并减少渗流，有几种方法来密封大坝的水库，在大坝的黏土心下建造防渗墙是最有效的方法之一。 。在这项研究中，Eyvashan土坝的渗透率和孔隙水压力，仪器结果与数值分析结果的比较，最后研究了防渗墙的性能。根据仪器和数值分析的结果，全油藏条件下的最大渗流率等于831,604 m ^3。/年。为了拟合仪器和数值分析的数据，使用了多元回归，并使用了确定系数 ，分别得出渗流和孔隙水压力的R ²  = 0.9892和R ² = 0.9834 。观测数据的结果与预测数据之间的非常好的一致性表明，根据孔隙水压力，大坝具有适当的性能。而且，由于数值模拟和仪器的结果，在隔断壁的下游部分中的孔隙水压力突然下降，这表明了隔断壁的正确操作。