What's the meaning of "Gravel(0/31.5)"?

[jasonl]

Does anybody know the meaning of "Gravel(0/31.5) in earthwork contract? Also,what is the classification of soil of "QS0,QS1,.,QS4"?
Jason

 

[bmike]

I am guessing that "Gravel 0/31.5" means gravel with a minimum size of 0 (mm) and a maximum size of 31.5 mm, which is 1-1/4" in Imperial units.

I have no idea what the others are.