LARE - Section 2 - Analysis – Soils Questions & Answers 100% Verified!!
Granular Soils - ANSWERparticle size ranges from .003" - .08" (sand) and .08" - 1" (gravel)
-known for their water-draining properties -obtain maximum density in either a fully dry or saturated state
Hydrologic Soil Group A - ANSWERsand, loamy sand or sandy loam types of soil
--low runoff potential and high infiltration rates even when thoroughly wet
Hydrologic Soil Group B - ANSWERsilt loam or loam
--moderate infiltration when thoroughly wetted
Hydrologic Soil Group C - ANSWERsandy clay loam
--low infiltration rates when thoroughly wetted
Hydrologic Soil Group D - ANSWERclay loam, silty clay loam, sandy clay, silty clay or clay
--highest runoff potential
anaerobic soil - ANSWERsoil that is devoid of interstitial oxygen normally occurs in wetlands because of sustained presence of water that limits contact with the atmosphere
Erosion factor K - ANSWERindicates the susceptibility of a soil to sheet and rill erosion by water
-values range from 0.05 to 0.69, higher the value, more susceptible soil is to erosion by water
Erosion factor T - ANSWERrate in tons per acre per year, estimate of the max average annual rate of soil erosion by wind/water that can occur w/out affecting productivity over a sustained period
Erodibility Index (EI) - ANSWERa numerical expression of the potential of a soil to erode, higher the index, the greater the risk
--scores of 8 or above = highly erodible land
Erodibility Ratings - ANSWERlow erodibility= .23 and lower
Moderate= .26-.36; loamy and clayey soils
High= .37 and higher; silty soils Shrinkage limit - ANSWERwater content, expressed as a % of the weight of the oven-
dried soil, where further loss in moisture will not cause a decrease in its volume
Unified Soil Classification System (USCS) - ANSWERclassifies soils according to properties that affect their use as construction material according to:
-grain-size (course is better)
-plasticity index (narrow range from the plastic limit to the liquid limit is better)
-liquid limit (low is better)
-organic matter content (well graded is better)
AASHTO classification system - ANSWERidentifies soils based on their suitability for highway subgrade use, Group A (high infiltration rate) through Group D (very slow rate)
Proctor test - ANSWERdetermines the maximum density of a soil needed for a specific job site, tests the effects of moisture on soil density shown as % of density, before any compaction takes place to develop compaction specs
modified proctor values are higher because they take into account higher densities needed for certain typed of construction projects
Modified Proctor Test - ANSWERrequires 4.5 more effort than required by the standard method, take into account higher required densities where minimal or no settlement can
be tolerated by the structure
nuclear density - ANSWERmeasures density by using radioactive isotope source at the soil surface, gives off photons that radiate back to the meter's detectors
-dense soil absorbs more radiation than loose soil
soil elasticity - ANSWERability of soil to return to original shape after being subjected to load condition, measure of soil stiffness
Agronomic Soil - ANSWERduring construction phase it verifies soil amendment performance and soil fertility to ensure soil is more productive for plant growth
Red soil - ANSWERindicates the presence of iron oxides in soil
blue or gray soil - ANSWERsuggests poor drainage and lack of good aeration in soil
dark brown or black soil - ANSWERindicates that the soil has a high organic matter content
lime - ANSWERcan be added to decrease the acidity of a soil
aluminum sulfate - ANSWERcan be added to increase the acidity of a soil
rill erosion - ANSWERformation of numerous small channels only several inches deep
Granular Soils - ANSWERparticle size ranges from .003" - .08" (sand) and .08" - 1" (gravel)
-known for their water-draining properties -obtain maximum density in either a fully dry or saturated state
Hydrologic Soil Group A - ANSWERsand, loamy sand or sandy loam types of soil
--low runoff potential and high infiltration rates even when thoroughly wet
Hydrologic Soil Group B - ANSWERsilt loam or loam
--moderate infiltration when thoroughly wetted
Hydrologic Soil Group C - ANSWERsandy clay loam
--low infiltration rates when thoroughly wetted
Hydrologic Soil Group D - ANSWERclay loam, silty clay loam, sandy clay, silty clay or clay
--highest runoff potential
anaerobic soil - ANSWERsoil that is devoid of interstitial oxygen normally occurs in wetlands because of sustained presence of water that limits contact with the atmosphere
Erosion factor K - ANSWERindicates the susceptibility of a soil to sheet and rill erosion by water
-values range from 0.05 to 0.69, higher the value, more susceptible soil is to erosion by water
Erosion factor T - ANSWERrate in tons per acre per year, estimate of the max average annual rate of soil erosion by wind/water that can occur w/out affecting productivity over a sustained period
Erodibility Index (EI) - ANSWERa numerical expression of the potential of a soil to erode, higher the index, the greater the risk
--scores of 8 or above = highly erodible land
Erodibility Ratings - ANSWERlow erodibility= .23 and lower
Moderate= .26-.36; loamy and clayey soils
High= .37 and higher; silty soils Shrinkage limit - ANSWERwater content, expressed as a % of the weight of the oven-
dried soil, where further loss in moisture will not cause a decrease in its volume
Unified Soil Classification System (USCS) - ANSWERclassifies soils according to properties that affect their use as construction material according to:
-grain-size (course is better)
-plasticity index (narrow range from the plastic limit to the liquid limit is better)
-liquid limit (low is better)
-organic matter content (well graded is better)
AASHTO classification system - ANSWERidentifies soils based on their suitability for highway subgrade use, Group A (high infiltration rate) through Group D (very slow rate)
Proctor test - ANSWERdetermines the maximum density of a soil needed for a specific job site, tests the effects of moisture on soil density shown as % of density, before any compaction takes place to develop compaction specs
modified proctor values are higher because they take into account higher densities needed for certain typed of construction projects
Modified Proctor Test - ANSWERrequires 4.5 more effort than required by the standard method, take into account higher required densities where minimal or no settlement can
be tolerated by the structure
nuclear density - ANSWERmeasures density by using radioactive isotope source at the soil surface, gives off photons that radiate back to the meter's detectors
-dense soil absorbs more radiation than loose soil
soil elasticity - ANSWERability of soil to return to original shape after being subjected to load condition, measure of soil stiffness
Agronomic Soil - ANSWERduring construction phase it verifies soil amendment performance and soil fertility to ensure soil is more productive for plant growth
Red soil - ANSWERindicates the presence of iron oxides in soil
blue or gray soil - ANSWERsuggests poor drainage and lack of good aeration in soil
dark brown or black soil - ANSWERindicates that the soil has a high organic matter content
lime - ANSWERcan be added to decrease the acidity of a soil
aluminum sulfate - ANSWERcan be added to increase the acidity of a soil
rill erosion - ANSWERformation of numerous small channels only several inches deep
