Question

5. An open cut section for an Ontario municipal roadbuilding contract required a subdrain installation of a 100 mm diameter plastic pipe. The subdrain trench was excavated in a soil with the following test data: ) Particle size analysiss Diameter (mm) 0.6 0.15 0.075 0.04 0.02 0.004 0.002 0.001 %passing 100 97 90 74 56 20 i) Atterberg Limits: PL 24; LL 22 For backfill, the contractor placed and compacted aggregate from a local pit meeting the Granular A specifications of OPSS 1010 Plot the gradation curves for the subgrade and backfill materials. Based on the materials, are there likely to be drainage issues with the performance of the subdrain? If so, what are the risks? Classify the subgrade soil (USCS, AASHTO) and identify any performance issues with this material a) b) c)

Answer 1

The Tanular OPSS Ioo, shown ún Uhe table matafal arc amn a a [ne-graired Sil ari

Gr LL 5D and4 and ptted bie The general rar senn-peutous The graubar sal h no hareas MC an

SIEVE ANALYSIS - subgrade SIEVE ANALYSIS backfill PARTICLE SIZE %OF FINER PARTICLE SIZE | % OF FINER S.NO S.NO 100 0.6 0.15 0.075 0.04 0.02 0.004 0.002 0.001 an 26.5 19 13.2 9.5 4.75 1.18 0.3 0.15 0.075 an 100 97 4 35 4 74 15 20 10 0

110 100 90 80 70 e60 2 50 40 30 20 10 10 0.001 0.01 0.1 subgrade soil Sieve opening(mm) backfill soil