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 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
Excavation Protection and Support
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
Soldier Pile and Lagging
Sheeting Wall
Internally Stabilized Rely on reinforced mass of soil Not appropriate if access to underground utilities is needed 1. Mechanically Stabilized Earth Systems (MSES) 2. Geosynthetic Reinforced Earth Systems (GRES) 3. Soil Nailing 4. Gravity and Cantilever Walls CIP or Precast Gabions Mechanically Stabilized Segmental Block
Evergreen Wall
T-Wall
Foundations Drilled Shaft Driven Piles Micropiles
24 Soil Maps GIS accessible maps are at 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