field & lab tests for highway design

[longisland]

hi all,
I'm fairly new to this arena so the questions may sound trivial to some but I'd appreciate very much if you guys can just put up with me & give me some pointers.
I'm involved in a 60km rural arterial road; the 1st 20 odd km are flat terrain predominantly of alluvialluim deposit. The rest are pretty much rolling to mountanous terrain as steep as 32 degrees.
1) I'd received a set of prescribed field & lab soil testing assignments but I need a second opinion.
2) We (as in my supervisor & myself) have assigned approximately 1 borehole per km; I purposely assign at high cut areas use probes as intermediate tests for cost consideration. Is there a guideline on field soil test assignment for highway? I did assigned borehole in proposed high fill areas( 4 berms at 6m each) Any other tests ought to be considered such as piezocone etc?
3) Any specific lab test procedure is to be adopted assuming we are facing predominantly cut slopes? (preliminary design with 7 benchs with slopes of 1 to 1.5; the no of bench ar as high as 7)

thanks for the input in advance
4) There are some bridges to be constructed & some eroded slopes to be repaired. What are the field & lab tests involved?

 

[Ron]

longisland...
Unless you are using a lot of fill or drastically cutting into slopes, your boring frequency is OK, as long as you supplement as you have indicated. The piezocone will give you lots of info for less effort, provided you are in soils amenable to this method.

Keep in mind that most roadway stresses are dissipated in the upper 2m of material, so deep borings are wasteful. I would prefer manual augers and coring on more frequent basis, say every 100m. This will allow you to pick up on problematic areas such as very clayey materials, organic materials or the like.

Proofrolling is a good technique to use as well.

As for field and lab tests, I would suggest classification index tests, moisture-density relationships, and stability (CBR or similar).....all correlated to the expected subgrade and base elevations.

You might also want to consider the use of a falling weight deflectometer for initial design and as a baseline after construction. This is a quick method that yields lots of excellent information.