Table 4. Grain-size scales — soil classification (modified from U.S. Army, 

 Corps of Engineers, Coastal Engineering Research Center, 1977). 



Unified Soils 

 Classification 



ASTM 

 Mesh 



mm 

 Size 



Phi 

 Value 



Wentworth 

 Classification 



COBBLE 



/kzzv 



COARSE 

 GRAVEL 



FINE GRAVEL 



A 



H 



I 



coarse 



medium 



fine 



SILT 



CLAY 



256.0 F -9-0 



•■>6.'d-. SS 



64.0 -6.0 



W///////a//. 



<c '/////////////.*. y//////,*?}. 9. '///. -. i*. ?/ 



'. 'i'£'////-'j' •?'<'/- 



4.76%;-2.25^ 



= 4.0 1:1-2.0 



w^wwmzKz-w 



y- 



1.0 0.0 



251 



0.5 



'AH'/////. 



gS«o 



0.42^1.252 



'i'o'K'// 



/////, y. ■?.<-//////,};!-. 



160 



0.25 2.0 



120 0.125 3.0 



frntm^m^ :<o\mt:?i:m 



^///////////L 



230 0.062 54.0: 



"^ 

 V 



$ 







I 

 I 



» 



*~' ; 0.0024 12.0 J> 



BOULDER 



COBBLE 



PEBBLE 



GRAVEL 



very 

 coarse 



coarse 



medium 



fine 



very fine 





vi 



II 



SILT 



CLAY 

 COLLOID 



34 



