Filter Performance of Embankment Dams by No Erosion Filter Test (Case study: Bar and Bidvaz Dam)

فصلنامه آب و توسعه پایدار

Article 9, Volume 8, Issue 4 - Serial Number 22, March 2022, Pages 69-76   

Document Type: Technical paper

DOI: 10.22067/jwsd.v8i4.2109.1077

Authors

Alireza Raeesosadat¹; Ali Akhtarpour^{* 2}; maliheh nazari³

¹MSc, Civil Engineering Department, Faculty of Engineering, Ferdowsi University of Mashhad, Iran.

²Associate Professor, Civil Engineering Department, Faculty of Engineering, Ferdowsi University of Mashhad, Iran.

³MSc student, Civil Engineering Department, Faculty of Engineering, Ferdowsi University of Mashhad, Iran

Abstract

Internal erosion and piping pose major hazards to earth dams. Experimental method of filter performance evaluation and design method based on criteria with simple parameters are the two main groups of filter selection and design in earth dams. Determining the appropriate gradation for the filter of earth dams, despite the apparent simplicity of experimental criteria, has posed important technical and economic issues for engineers in large numbers of large projects. This problem has become larger in situations where the clay soil is dispersive or suspected of dispersivity because on the one hand, estimating the true potential of dispersivity is not easy due to the multiplicity of detection tests, and on the other hand, the application of few criteria in filter design prevents erosion of available dispersive soils, usually leading to the selection of very fine and costly gradation. With this approach, a no erosion filter test device was made to perform laboratory tests and study the accuracy of the design methods. As a case study, by performing basic dispersivity experiments on the clay core samples of Bar Neishabour and Bidvaz Esfarayen dams, the degree of dispersivity potential in these soils was determined. By performing a number of No Erosion Filter tests, the best grain size of the filter, which prevents the erosion of the soil of Neishabour Bar Dam at different pressures, was obtained with an accuracy of 0.1 mm which is different from the filter executed in the dam. Also by testing the design criteria and the laboratory method of filter design for the core soil of Bidvaz Esfarayen dam, it was found that there is a big difference in the results of each design method.

Keywords

Filter Design Criteria; Internal Erosion; No Erosion Filter Test; Dispersivity

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