benching trench backfill on road crossing??
benching trench backfill on road crossing??
(OP)
every time i go over a depressed road crossing repair (where the water company has excavated a trench to re lay a pipe)i wonder if it would not be better practice to bench the trench so that there is more friction on the sides. Basically you would make the excavation a bit wider for the top 150mm then step it in for the next 150mm and then maybe have the same width for the rest of the trench depth.
when you backfill your top two layers will be supported on the existing road layerworks at the edges, but i am not sure if they would have any tensile strength across the trench if there is settlement in the trench bckfill
I never see this happening and was just wondering if it would reduce the effects of settlement/poor workmanship?
when you backfill your top two layers will be supported on the existing road layerworks at the edges, but i am not sure if they would have any tensile strength across the trench if there is settlement in the trench bckfill
I never see this happening and was just wondering if it would reduce the effects of settlement/poor workmanship?





RE: benching trench backfill on road crossing??
RE: benching trench backfill on road crossing??
The municipality needs to be more diligent in their trench repair requirements and testing. In my area, up until about 20 years ago, all roadway crossings were required to be compacted in lifts and tested at various levels. The base material under the asphalt had to be compacted to 100% of the Modifed Proctor maximum dry density....tight requirement. Few of those crossings were ever an issue. Now those requirements have been relaxed and we have bumpy lumpy roads!
RE: benching trench backfill on road crossing??
With regards to the local municipality, please don't get me started!!
RE: benching trench backfill on road crossing??
RE: benching trench backfill on road crossing??
No. Benching with lower compaction will not reduce the amount of depression you get in a trench from subsequent traffic. The vertical deflection that causes such a depression is caused by increased compaction of the soil. Keep in mind that compaction from the vibration of traffic will occur before significant increases in shear strength of the soil and before such shear strength is mobilized by loading.
RE: benching trench backfill on road crossing??
RE: benching trench backfill on road crossing??
What about sloping out the trench sides just a bit, rather than benching.
RE: benching trench backfill on road crossing??
RE: benching trench backfill on road crossing??
Benching it seems like a whole lotta' more work and cost.
RE: benching trench backfill on road crossing??