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<br />The Factor of Safety against sliding is expressed as the ratio of <br />resisting forces to forces causing shear. <br /> <br />F. S. = E Sf <br />2 Sx <br /> <br />The F. S., independent of cohesion is: <br /> <br />F.S. = <br /> <br />o <br />45,244 tan 26 <br />18,539 <br /> <br />= 1. 19 <br /> <br />and with minimum cohesion: <br /> <br />F.S. = <br /> <br />o <br />10 x 700 + 45,244 tan 26 <br />18,539 <br /> <br />= L 56 <br /> <br />"'\. <br /> <br />Other caIcuIations indicated the same degree of safety. This type <br />of analysis indicates the dam is safe from shear failure, but with a very small <br />- safety factor. This small degree of safety makes it imperative that corrective <br />action be taken on the "piping" that is occurring and causing the subsidence of <br />the downstream slope. Any reduction in materiaI on the downstream face <br />reduces to resisting forces and, therefore the Factor of Safety is reduced. <br /> <br />Analyses were made on the horizontal sliding on or within the foundation <br />assuming a cleavage plane 10 feet below the straight line projection of the <br />embankment. An illustration of this procedure is given herein and referenced <br />to Sheet 2 for symbol denotation. The following assumptions were made: <br /> <br />WI = 60 pet ~ saturated foundation material <br />W = 110 pcf - dry unit weight of embankment <br />The measured angles are: <br />o <br />81 = 10 Rad. = .174 <br /> <br />82 = 60 " = .104 <br />83 = 1350 " = 2.36 <br /> <br />III-5 <br />