Lineditch Deletion

[junpal]

I am working as a planning engineer here in Palau, I have a problem regarding proposal for deletion of lineditch at the top of the cutslope can anyone help me what are the possible reasons for such deletion of lineditch because the design slope is not workable to put up lineditch because it is very high and full of vegetation and I think the contractor will not approve such reason.... But the slope is stable did not experience such failure up to now since it was constructed, also there are vegetation at the top of the cut can I reason this as catchment of water and control its runoff?

Thanks

 

[VAD]

Hello Junpal:

Your line ditch is I take it a "catchwater ditch" as is oftn referred to in some parts. This ditch acts to prevent upland runoff from going down the slope face and is often a detail that is used in geometric design for high cuts.

Depending on past evidence etc one can eliminate or in circumstance where there is a positive stream or flow to ward slope then this ditch is advantageous. However very often this ditch can preceipitate slides from the slope crest. To be on the safe side if the ditch is used it should be lined to prevent water percolating from the drain downwards.

You have to balance the removal of vegetation with the construction of the ditch. Vegetation clearing if done indisciminately can cause problems as well to a stable slope.

My suggestions is that you review the past performance of the slope, look at the land contours, take a hike uphill, take in the fresh air, do some thinking, take some photos, then descend the hill. These will provide inspiration and answers that you can provide.

 

[cvg]

In addition to VAD's good advice, consult a local geotechnical engineer to evaluate the slope stability...