Experimental Study For Pizometric Head Distribution Under Hydraulic Structures
Dr. Najm Obaid Salim Alghazali, Hala Kathem Taeh Alnealy
Index Terms: Flow net , Inclined cut-off, Hydraulic structures ,soil , seepage tank.
Abstract: In this research the experimental method by using Hydraulic modeling used to determination the flow net in order to analyses seepage flow through single- layer soil foundation underneath hydraulic structure. as well as steady the consequence of the cut-off inclination angle on exit gradient , factor of safety, uplift pressure and quantity of seepage by using seepage tank were designed in the laboratory with proper dimensions with two cutoffs . The physical model( seepage tank) was designed in two downstream cutoff angles, which are (90, and 120°) and upstream cutoff angles (90, 45, 120°). After steady state flow the flow line is constructed by dye injection in the soil from the upstream side in front view of the seepage tank, and the equipotentials line can be constructed by pizometer fixed to measure the total head. From the result It is concluded that using downstream cut-off inclined towards the downstream side with Ө equal 120º that given value of redaction (25%) is beneficial in increasing the safety factor against the piping phenomenon. using upstream cut-off inclined towards the downstream side with Ө equal 45º that given value of redaction (52%) is beneficial in decreasing uplift pressure and quantity of seepage.
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