Goals: Participants will have a better understanding of soil boring reports, soil testing and soil test reports. Participants will be able to read, un

Transcription

1 Understanding Soils and Boring Reports Dr. Norman Hummel Hummel & Co. Inc. (

2 Goals: Participants will have a better understanding of soil boring reports, soil testing and soil test reports. Participants will be able to read, understand, and use soil test reports.

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5 When is Exploratory Work Used New Construction Evaluate soils, subsoils, other elements in the soil profile prior to construction May yp provide direction for design and construction. Existing Fields Diagnose soil problems in existing fields

6 Information Sought Impenetrable layers Bedrock? Depth to ground water Will subsurface drain system be needed? Soil types present Can it be reused, modified, d or all imported? Permeability to water

7 Sampling Methods - Preconstruction Soil Augers Hammers with sample tubes Excavation equipment

8 Sampling Methods Existing Fields

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15 Soil The unconsolidated mineral or organic material on the immediate surface of the earth that serves as a natural medium for the growth of land plants.

16 SOIL - Has been subjected to and shows the effects of genetic and environmental factors of climate (water and temperature) and micro and macroorganisms, conditioned by relief, acting on parent material over a period of time.

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18 Properties of Soils Biological Chemical Physical

19 Soil Physical Properties Texture Structure Density Influence on porosity (total, micro, macro) Soil water Saturated hydraulic conductivity (infiltration) Unsaturated hydraulic conductivity Water content, water retention characteristics

20 Soil Texture e Division of soil particles according to size: sand, silt, clay. Textural classes determined by percentage of each. Influences physical properties of the soil: porosity, pore space distribution, compressibility, and drainage characteristics.

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25 Soil Classification Systems Unified Soil Classification System ASTM D2487, test based Textural analysis, plasticity index Visual/Manual Description of Soils ASTM D2488, visual based Used primarily il for engineering i purposes Very comprehensive, definitive

26 LL liquid limit CL Sandy lean clay ML - gravelly silt with sand and cobbles

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28 Sieves es AASTO Sieve Number Sieve Size # mm Coarser is gravel #8 228mm 2.28 # mm # mm # mm # mm # mm Separates sand from silt and clay

29 Soil Classification Systems - USDA 12 soil textural classes Used primarily in description of planting soils.

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31 Sieves es USDA Sieve Number Sieve Size #10 2 mm Coarser is gravel #18 1mm # mm # mm # mm # mm Separates sand from silt and clay

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34 Can we amend soils to change soil texture? Yes!

35 Considerations in Amending Soils with Sand Sand particle size distribution Amount of sand to add Composition of sand (calcareous vs. silica) Sand particle shape

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38 Recommendations Based on Ohio State Research ASTM C-33 concrete sand with Cu < 4 and fineness modulus of 2.5 to 3.2. Sand content of about 65 75% Organic matter content of 4 8% by weight.

39 ASTM C-33 Concrete Sand Sand Size % Passing 4.75 mm (No. 4) % 2.36 mm (No. 8) % mm (No. 16) 50 85% 0.60 mm (No. 30) 25 30% 0.30 mm (No. 50) 5 30% 0.15 mm (No. 100) 0 10%

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42 Soil Bulk Density Unit weight of dry soil (g/cc, pcf) Influenced by soil texture sandy soils higher than fine textured soils. Decreases with increasing organic matter. Directly related to porosity. Directly affects drainage. Reported in lb/cu ft or g/cc. Conversion (g/cc x 62.4 = lb./cu. ft.)

43 Soil Bulk Densities Sandy soils 1.4 to 1.7 g/cc Fine textured soils to16g/cc 1.6 Also heavily influenced by organic content So what is dense (compacted)?

44 Proctor Testing

45 /c u ft) Dens ity ( lb Moisture Density of gravelly sandy loam soil (5.8% OM) 0% 5% 10% 15% 20% Soil moisture content (%)

46 Moisture Density Relationship of Sand Based Structural Soil (Lab ID No ) 1) ity (lb /c u. ft.) Dens % 2% 4% 6% 8% 10% 12% 14% 16% 18% 20% Soil Water Content (%)

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49 Other Test Parameters amete Saturated Hydraulic Conductivity Porosity Air filled Water filled Density

50 Saturated Hydraulic Conductivity (Infiltration rate) rate at which soil core conducts water.

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56 Porosity voids existing between sand and soil particles, or within soil aggregates. Macroporosity (aeration) larger pores that conduct water under saturated conditions, filled with air when evacuated. Microporosity (capillary) smaller pores that hold water against gravitational forces.

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63 Organic Matter Increases soil cation exchange capacity Increases microbial populations p and activity Improves soil physical conditions Lower density, increased porosity Improved structure Increased infiltration Increased water holding capacity

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65 Compost Quality for Amending Soils Color brown to black Screened to ½ inch Organic matter content > 30% Moisture content t 30 60% C/N ratio 15:1 to 30:1

66 Compost Quality for Amending Soils Solvita Maturity Index 5 to 8 ph of 6 to 8 Meet EPA or state guidelines EC of < 4.0 ds

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69 Chemical Testing Sample soil to be used as topsoil (on-site, stockpile) Use lab you are familiar with. Use lab that provides recommendations

70 Chemical Testing What s ph, ph buffer Important Phosphorus, potassium Calcium, magnesium, sodium Micronutrients i t Nitrogen?

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