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Session 3 Site Conditions

Session 3 Site Conditions. Topic 1 Geotechnical. Test Boring Logs. Laboratory Test Results. Moisture density test (proctor). “The perfect dirt ball”.  d MAX. Dry Unit weight (  d ). Dry & crumbly. Wet & mushy. OMC. Moisture Content (MC).

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Session 3 Site Conditions

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  1. Session 3 Site Conditions Topic 1 Geotechnical

  2. Test Boring Logs

  3. Laboratory Test Results

  4. Moisture density test (proctor) “The perfect dirt ball” dMAX Dry Unit weight (d) Dry & crumbly Wet & mushy OMC Moisture Content (MC)

  5. Required dry unit weight = 121.3 pcf x 0.95 = 115.2 pcf Acceptable MC = 10 – 12%

  6. Loose Lift Thickness: Max 12” / Min 8” Retest PASS FAIL No. X X X X X 6 X SPECIFICATION REQUIREMENTS Material type: MSEW soil; MSE wall “D” Required % Compaction: >90% Max dry density Required Moisture Range: +/- 5% of OMC Test Location Sta # / Distance (ft) From MSE face Lift Elevation Sta 9+50 / 14 ft 272.0 See page 7.4-36

  7. Compaction control for oversize material • For soils with up to 30% retained on the ¾” sieve. Standard proctor with oversize correction • For soils with more than 30% retained on the ¾” sieve “For backfills containing more than 30 percent retained on the 19 mm sieve, a method compaction consisting of at least four passes by a heavy roller shall be used.”

  8. Description of Subsurface Conditions • Represents the geologist/engineersinterpretation of the logs and tests • May be presented as a subsurface profile drawing

  9. Conclusions and Recommendations • Are based on description of subsurface conditions • Are what the design should have been based on

  10. Soils • Coarse grained (Cohesionless soils) • Fine Grained (Cohesive Soils)

  11. POWDERED SUGAR Coarse Grained Soils (Identified by grain size) Boulders >305 mm (>12”) Cobbles 76 - 305 mm (3 -12”) Gravel 4.76 - 76 mm (#4 – 3”) Sand 0.074 - 4.76 mm (#200 - #4)

  12. Fine Grained Soils(Identified by behavior)

  13. Soil Classification Systems • USCS • AASHTO

  14. Rock

  15. Rocks are Identified by Origin and Type Igneous Rock: Granite, Diorite, Basalt Sedimentary Rock: Sandstone, Limestone, Shale Metamorphic Rock : Gneiss, Schist, Quartzite

  16. 140 lb Hammer dropping 30” 4 blows for 6” 7 blows for 6” 6 blows for 6” SPT Resistance (N-value) = 7 + 6 = 13 Standard Penetration Test

  17. Split Spoon Vent Sampler Head Ball Check Valve Split Barrel Sampling Tube Driving Shoe

  18. Consistency(Fine Grained soils)

  19. Strength/ Hardness

  20. Recognition of a Water Problem

  21. Impacts of Groundwater

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