Soils - HDM Chapter 9 All pictures from HDM Ch 9

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Soils - HDM Chapter 9All pictures from HDM Ch 9
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Subsurface Sampling

• Test Pit
• Probe Hole (probeno samples does it hit an
  obstruction)
• Auger
• Split Spoon Sampling
• Undisturbed Sampling

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Subsurface Exploration

• Split spoon sampling

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Subsurface Exploration

• Undisturbed sampling

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Other

• Rock Core Drilling
• Observation well
• Geophysical exploration
• Cone penetrometer
• Retractable plug sampling
• Falling-weight deflectometer (soil strength under
  pavt)

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Alignment from Geotechnical POV

• Fill of 2-3 m
• Spans irregularities
• Free of drainage problems
• Avoid skim fills
• Cuts
• Avoid skim cuts
• Avoid groundwater
• Avoid side hill cuts

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Unsuitable Material

• Peat, muck, topsoil, sod (organics)
• Landfill, industrial waste
• Sludge
• Removed and replaced with suitable material

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Soil Issues

• Settlement
• Slope Stability
• Rock Cuts
• Excavation Protection and Support
• Design of Spoil Sites
• Optional Borrow Areas
• Geotextiles

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Settlement

• Reduce profile
• Lightweight fill
• Surcharge
• Sand drains
• Wick drains

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Stability
Lower profile Stabilizing berm Benching Staged
Construction Retaining Wall Geofabrics
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Rock Cuts

• Wire Mesh
• Rock buttress
• Fence

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Excavation Protection and Support
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Spoil Sites

• Burning of solid waste is prohibited
• Design so that excess material (not marketable or
  recyclable) is used in the existing right-of-way

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Optional Borrow Areas

• Identify borrow areas within existing right-of-way

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Geotextiles

• Bedding/Separation/Drainage/Slope
  Protection/Stabilization
• Class I (strongest) to Class III (least strong)
• Woven and NonWoven

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Externally Stabilized

• Anchored Walls
• Anchored to earth or bedrock
• Deadman anchors
• Grouted tiebacks
• Soldier Pile and Lagging
• Piles at set intervals
• Lagging placed between piles
• Sheeting
• Driven to a certain depth
• Usually steel

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Soldier Pile and Lagging
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Sheeting Wall
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Internally Stabilized

• Rely on reinforced mass of soil
• Not appropriate if access to underground
  utilities is needed
• Mechanically Stabilized Earth Systems (MSES)
• Geosynthetic Reinforced Earth Systems (GRES)
• Soil Nailing
• Gravity and Cantilever Walls
• CIP or Precast
• Gabions
• Mechanically Stabilized Segmental Block

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Evergreen Wall
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T-Wall
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Foundations

• Drilled Shaft
• Driven Piles
• Micropiles

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Soil Maps

• GIS accessible maps are at http//websoilsurvey.nr
  cs.usda.gov/app/
• Hints
• AOI (polygon double click to end)
• Soil Data Explorer
• Soil Properties and Qualities
• Soil Qualities and Features
• Hydrologic Soil Group
• View Rating
• Printable Version