frwo other measures commonly are employed. Geologists often use 



W.„ 



x 100 



w s + w w 



where wc Ss the water content expressed as a percentage of the total wet wel 

 (W s + W w ) of the sediment sample; a useful conversion is 



TOOwc 

 w = 



100 -wc 



The third measure, particularly applicable to water -saturated sediments, Ss the 

 void ratio, e, which is the ratio of the volume of void space, V v , to the volume of 



solid particles, V s , in a given sediment mass (ASCE), or 



e = ^ . (10) 



Void ratio is determined in the laboratory from 



e = S ' W - 1 . (11) 



w s 



where T w fa the unit weight of. water . 



In Appendix B tables, void ratio also is recomputed at 100 percent saturation from 

 the equation 



'sat 



G s w 

 100 



Porosity, n, is the ratio in percentage of the volume of voids In a given mass, 

 V v , to the total volume of the sediment mass, V (ASCE), or 



V 

 n = — x 100 



V 



23 



