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Soils - HDM Chapter 9 All pictures from HDM Ch 9. Subsurface Sampling. Test Pit Probe Hole (probe—no samples; does it hit an obstruction) Auger Split Spoon Sampling Undisturbed Sampling . Subsurface Exploration. Split spoon sampling. Subsurface Exploration. Undisturbed sampling. Other.
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Subsurface Sampling • Test Pit • Probe Hole (probe—no samples; does it hit an obstruction) • Auger • Split Spoon Sampling • Undisturbed Sampling
Subsurface Exploration • Split spoon sampling
Subsurface Exploration • Undisturbed sampling
Other • Rock Core Drilling • Observation well • Geophysical exploration • Cone penetrometer • Retractable plug sampling • Falling-weight deflectometer (soil strength under pavt)
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
Unsuitable Material • Peat, muck, topsoil, sod (organics) • Landfill, industrial waste • Sludge • Removed and replaced with suitable material
Soil Issues • Settlement • Slope Stability • Rock Cuts • Excavation Protection and Support • Design of Spoil Sites • Optional Borrow Areas • Geotextiles
Settlement • Reduce profile • Lightweight fill • Surcharge • Sand drains • Wick drains
Stability Lower profile Stabilizing berm Benching Staged Construction Retaining Wall Geofabrics
Rock Cuts • Wire Mesh • Rock buttress • Fence
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
Optional Borrow Areas • Identify borrow areas within existing right-of-way
Geotextiles • Bedding/Separation/Drainage/Slope Protection/Stabilization • Class I (strongest) to Class III (least strong) • Woven and NonWoven
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
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
Foundations • Drilled Shaft • Driven Piles • Micropiles
Soil Maps GIS accessible maps are at http://websoilsurvey.nrcs.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