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Construction
Soil
Term | Definition |
---|---|
Site Work | usually performed by professionals |
Legal History | Title search Usually performed by a professional such as an attorney or title search agency |
Legal History | Check to see that no outstanding liens are held against the property;All previous title transfers correctly recorded; Zoning status ;Master plan for the local municipality |
Legal History | Transportation plans;Property zoning setback requirements Easements;Future plans for the land and surrounding areas and Boundaries |
Physical Characteristics | General topography of the property which impact site development costs;Existing utilities (above ground, utility boxes) Neighborhood demographics and characteristics;Drainage |
Physical Characteristics | Soil conditions composition of the soils;Compaction test results Geology of the area |
Consolidation | Means the removal of water-filled porosity; For most engineering purposes, the denser a soil is the better its load-bearing capacity; To make a soil more dense requires removing as much of the porosity as possible. |
Soil compaction | Removal of air-filled porosity |
Soil mechanics | Deals with soil response to physical stress; Stress may be weight of a building, vehicle traffic, or various other forces; Various classification systems have been devised to evaluate soil suitability for engineering purposes. |
Soil consistency | Refers to the soil's response to stress |
Stress | Pressure applied to the soil; In physics, pressure is force per area; Force applied to soil is normally weight. |
Strain | The response to stress |
Yield point | Point at which a material fails (deformability and firmness of a soil); Often plotted as a function of stress by engineers. |
Soil Classification Systems | (1) a grain-size distribution curve (or gradation curve), and (2) the Atterberg limits (or soil consistency). The grain-size analysis can be either mechanical or with a hydrometer analysis. |
Most widely used classification systems | Unified Soil Classification System (USCS); American Association of State Highway and Transportation Officials (AASHTO) |
Triangular soil classification | U.S. Department of Agriculture developed a grain size classification system that names soils depending on the percentages of sand, silt, and clay. |
Atterberg Limits | System used to describe the shrinkage limit, plastic limit, and liquid limit of a soil. ;As water is added to a dry soil, the soil changes from solid to semi-solid to plastic to liquid. |
Plastic limit | Moisture content in the soil at the threshold between semi-solid and plastic.Determined by rolling a thread of soil on a glass plate until the 1/8-inch diameter thread begins to crumble ;Explained in ASTM procedure D-4318 |
Liquid limit | Moisture content in the soil at the threshold between plastic and liquid ;Determined by forming a groove in a dish of soil and impacting the dish until the groove closes ;Done following the ASTM procedure D-4318 |
Large liquid limit | indicates high compressibility and high shrink swell tendencies |
Plasticity index (P) | Range of moisture content in which the soil remains plastic (Higher the PI rating, the greater the shrink-swell potential); Determined by subtracting the plastic limit from the liquid limit |
Shrinkage limit | Water content, expressed as a percentage of the weight of the oven-dried soil, at which further loss in moisture will not cause a decrease in its volume |
AASHTO classification system | American Association of State Highway Officials classification system identifies soils based on there suitability for highway subgrade use ;Uses a variety of index parameters to classify soil |
Soil Classification Group A | Has a high infiltration rate (low runoff potential) when thoroughly wet ;Consists mainly of deep, well drained to excessively drained sands or gravelly sands ;Has a high rate of water transmission. |
Soil Classification Group B | Has a moderate infiltration rate when thoroughly wet ;Consists chiefly of moderately deep or deep, moderately well drained or well drained soils that have moderately fine texture to moderately coarse texture ;Has a moderate rate of water transmission |
Soil Classification Group C | Has a slow infiltration rate when thoroughly wet:Consists chiefly of soils having a layer that impedes the downward movement of water or soils of moderately fine texture or fine texture ;Has a slow rate of water transmission. |
Soil Classification Group D | Very slow infiltration rate (high runoff potential) when saturated. ;Clays that have a high shrink-swell potential;Soils that have a permanent high water table; |
Soil Classification Group D | Very slow infiltration rate ;Soils that have a clay layer at or near the surface;Soils that are shallow over nearly impervious material.;Has a very slow rate of water transmission. |
G | Gravel |
S | Sand |
M | Silt |
C | Clay |
O | Organic |
PT | Peat |
W | Well graded |
P | Poorly graded |
L | Low liquid limit compressibility; lean (clay);Low liquid limit; (silts); plasticity |
H | High liquid limit, compressibility; fat (clays) |
Soils | Soil characteristics are determined from test results, records, field experience and state and local specialists. |
Bedrock | General term for solid rock that lies beneath soil, loose sediments, or other unconsolidated material; Best foundation for a building. |
Boulder | Rock that can only be lifted with two hands or equipment |
Cobble | Rock that you can pick up with one hand |
Loam | Mixture of two or more soil ingredients |
Soil | Any particulate; Sediments or other accumulations of solid particles produced by the physical and chemical disintegration of rocks; Usually found on top of the parent rock formation; Classified by the grain size distribution of the particles. |
Coarse grained soils | Grains large enough to be seen |
Gravel | Can be picked up with thumb and forefinger |
Sand | Particles large enough to be seen but too small to be picked up individually; Coarse soil with little or no fine particles (5 mm to 0.010 mm) |
Fine grained soils | Grains too small to be seen; Cohesive in nature; Tends to compress |
Silt | Finer than sands, but coarser than clays; Slightly finer material is classified as (0.010 mm to 0.005 mm) |
Clay | Consist of microscopic flake |
Cohesive Soils | Able to maintain measurable shear force in the absence of confining forces |
Frictional Or Cohesionless Soils | Shear capacity is directly proportional to the confining force |
Peat And Other Organic Soils | Unsuitable |
High Plasticity Clays | With actual soil samples to verify that construction work may proceed safely |