File Entry: Determination of the height of vertical filter in heterogeneous earth dams with vertical clay core

In order to determine the height of the filter in heterogeneous earth dam, three embankment models were provided in a flume laboratory, with the length of 4.2 m at the base of dam, the width of 60 cm and the height of 1 m and body slope 1H: 2V. For embankment of model, two types of fine and coarse grained soils were used. The texture of the soil was made using hydrometer method. In the first model, the fine-grained and coarse-grained soils were used in downstream and upstream of the dam crest respectively. In Models 2 and 3 with cutting fine grained soil from the toe of the dam to the dam crest, vertical clay core was replaced. Index of a / L (a thickness of clay core and L is the length of base dam) was 1.7 and 1.10 in the second and third models respectively. Seepage experiments in 3 water height of 80 and 55 and 30 were performed. The phreatic surface was determined using wells and 30 embedded Piezometer in the models. Then rate of falling head due to clay core was measured and it compared with software PLAXIS V 8.5 results. Height of filter the clay core with safety factor 1.2 (Encounter Line Leak with 20% of the bottom filter) was introduced. The thickness and hydraulic conductivity of the clay were affected decline of water level.