Investigating the Economic Effect of Using Geotextiles in Filters and Drainage in Earth Dams

When leakage current goes in a coarser material from a relatively fine-grained soil, the fine-grained materials may move from their place, causing instability throughout the structure. In this case, the fine grains may fill the empty spaces of the drainage system, and prevent the movement of water in this part. Therefore, it will be necessary to create a filter in the structure. In earth dams with normal conditions, the use of granular filters is considered as the first option. If due to problems such as the preparation of aggregates or its high cost, the use of a variety of geosynthetics, especially geotextiles, which eliminates almost all the disadvantages of the traditional method, is recommended. In this research, through modeling a sample of an earth dam (Ahouyieh Baft dam), the effect of geotextile on drainage and its filtration according to different discharge values ​​has been investigated. By conducting this type of research, the optimal mode of filtration, which is a combination of granular filters and geotextile layers, can be obtained and used in the design of dams. After constructing 61 models (1 real dam model and 60 software models using geotextile), the results of real dam model including filter and grain drainage with a thickness of 50 cm were compared with models with geotextile filter and drainage. The model with a granular filter with a thickness of 10 cm and 5 layers of type 2 geotextile with a cost reduction of 40.53% was selected in the filter section as an alternative to the granular filter with a thickness of 50 cm.