Table A-1. Grain size scales (soil classification ). 



Unified Soils 

 Classification 



ASTM 

 Mesh 



mm 

 Size 



Phi 

 Value 



Wentworth 

 Classification 



COBBLE 



COARSE 

 GRAVEL 



FINE GRAVEL 



mmmmmmm-Am. 



S 



A 

 N 

 [0 



coorse 



medium 



fine 



SILT 



CLAY 



*ft*}.K.mn9*} 



256.0 ;-$.0 



.mi^:^^-i^m. 



i,'.M.'.'JU^WAWfiii.i'.'''.'.'.iJJ.iJJMiUAi.«.ii 



ii 64.0 li- 6.0^ 



:> 



TTirZ' 





f ff 99 ^T^^T 



TV. 



///y. . . ///////y. . .. . . . ///, /. 



p 



1,01 



4.0 -2 



^ -iTo 



i m i jjjuju i^j. ' im^^J l ^ ' 



m^ 





 



: .25 



0.5 3 1.0 



9rr9f>fi 



^ — , — \-~^. — f\ 



J.2_, ^ 



=0 



W/ 



^ 





^. . I i.i.y.i ■.IMP.-.-. . - 



ii60;r;3:;:|0.25 2.0 



•^^f 1 20 s Id! I 25 3 : : : 3 . 



^ 



^mmmm^^dmm. 



"•>.M^.^".\W.H" 



230 0.062 4.0 



=> 



< f^;^.y#^v<<^x:.Q..0.O39 8.0 ^ > 



p,"Ml",«-.^'WVW(.ii.i,« ■■.■».«■»(«« -■«»"."«'> 



rT^-TT-TTT-r^^-^-^ 12.0 



BOULDER 



COBBLE 



PEBBLE 



GRAVEL 



very 

 coorse 



coorse 



medium 



fine 



very fine 



S 



A 

 N 

 



SILT 



CLAY 



COLLOID 



Phi value (<?>) = log2 x diameter (mm) . 



A-41 



