Design of a 200m high slope in clay
Design of a 200m high slope in clay
(OP)
We are doing an investigation for a mine where one of the walls will be in transported unconsolidated sediments. The envisaged height of this wall will be up to 200m.
The profile consists of 0-60m-Gravelly sandy CLAY; 60-100m - Sandy silty Clay and silty clays; 100-140m- Organic Silty Clay; 140-160 - Silty Clay and extremely weathered shale (silty Cly) from 160-200m.
The water table sits at a depth of 70m from the surface.
What types of laboratory tests should be conducted?
What cell pressures should be used on Consolidated undrained tests?
The profile consists of 0-60m-Gravelly sandy CLAY; 60-100m - Sandy silty Clay and silty clays; 100-140m- Organic Silty Clay; 140-160 - Silty Clay and extremely weathered shale (silty Cly) from 160-200m.
The water table sits at a depth of 70m from the surface.
What types of laboratory tests should be conducted?
What cell pressures should be used on Consolidated undrained tests?





RE: Design of a 200m high slope in clay
Several things about your situation cuase all kinds of alarm bells. First, 200m soil slope is significant no matter what kind of slopes you work on. Second, "extremely weathered shale" could be a real trouble maker depending on the beding angle, type of material, etc. Will likely need to perform direct shear testing parallel to the beding plane in that material. Last, you have a relatively high water table.
Now for you specific questions. First the cell pressures should cover the range from at least 20 to 100 psi. Second type of tests should include index tests, CU with pore pressure measurement, UU, direct shear and dry density. The index tests would include natural moisture content, Atterburg limits, and possibly some grain size.
Good luck.
RE: Design of a 200m high slope in clay
RE: Design of a 200m high slope in clay