HomeMy WebLinkAbout32 91 13 Soil PreparationTHE KENT
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SECTION 329113 SOIL PREPARATION
PART 1 GENERAL
1.1 SUMMARY OF WORK
A. Scope of Work: The work covered by this section of the specifications consists in furnish-
ing all labor, equipment, hardware, and material necessary in performing work for and reasonably
incidental to complete the installation of:
1. Soil placement
2. Manufactured topsoil
3. Native topsoil amendments
B. Provide all soils as shown on the drawings or inferable there from and/or as specified in
accordance with the requirements of the Contract Documents.
C. These specifications include standards necessary for and incidental to the execution and com-
pletion of soil preparation, including hauling and spreading of planting soil mix and finished
grading as indicated on the prepared drawings and specified herein.
D. Protection of Existing Features: During construction, protect all existing trees, shrubs, and
other specified vegetation, site features and improvements, structures, and utilities specified
herein and/or on submitted drawings. Removal or destruction of existing plantings is prohibit-
ed unless specifically authorized by the Owner.
1.2 SUBMITTALS
A. Manufacturer’s Data: Submit copies of the manufacturer’s and/or source data for all materials
specified.
B. Qualification Data: For firms and persons specified in “Quality Assurance” Article to demon-
strate their capabilities and experience. Include lists of completed projects with project
names and addresses, names and addresses of Landscape Architects and Owners, and
other information specified.
C. Samples:
1. Submit samples of all topsoil, soil mixes, organic and mineral mulches, and organic ma-
terials. Samples shall weigh 2 lbs. and be packaged in plastic bags. Samples shall be
typical of the lot of material to be delivered to the site and provide an accurate indication
of color, texture, and organic make-up of the material.
2. Drainage gravel.
C. Soil Test: Submit soil test analysis report for each sample of topsoil and planting mix from
a soil-testing laboratory recognized by the State Department of Agriculture, with the
experience and capability to conduct the testing indicated.
1. Provide a particle size analysis, including the following gradient of mineral content:
USDA Designation Size in mm
Gravel +2 mm
Very course sand 1 – 2 mm
Course sand 0.5 – 1 mm
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Medium sand 0.25 – 0.5 mm
Fine sand 0.1 – 0.25 mm
Very fine sand 0.05 – 0.1 mm
Silt 0.002 – 0.05 mm
Clay smaller than 0.002 mm
2. Provide a chemical analysis, including the following:
a. pH and buffer pH.
b. Percentage of organic content by oven-dried weight.
c. Nutrient levels by parts per million, including phosphorus,
potassium magnesium, manganese, iron, zinc, and calcium. Nutrient test shall
include the testing laboratory recommendations for supplemental additions to the
soil based on the requirements of horticultural plants.
d. Soluble salt by electrical conductivity of a 1:2 soil: water, sample measured in
millimho per cm.
e. Cation exchange capacity (CEC).
D. Material Testing: Submit the manufacturer’s particle size analysis, and the pH analysis
and provide a description and source location for the content material of all organic
materials.
1.3 QUALITY ASSURANCE
A. Workmanship: All workmanship and finishes shall be first class in all respects, and in
accordance with the best practice. These drawings and specification describe the scope of
work but do not show or describe all work or material that may be required for full
performance and completion of the contract documents. On the basis of the scope shown
herein, Contractor shall furnish and install all parts required for the proper execution and
completion of the work. Any item included will require the contractor to furnish and install all
parts needed for a complete installation.
B. Soil-Testing Laboratory Qualifications: An independent laboratory, recognized by the State
Department of Agriculture, with the experience and capability to conduct the testing indicated
and that specializes in types of tests to be performed.
C. Topsoil Analysis: Furnish soil analysis by a qualified soil-testing laboratory stating
percentages of organic matter; gradation of sand, silt, and clay content; deleterious material;
pH; and mineral and plant-nutrient content of topsoil.
1. Report suitability of topsoil for lawn/plant growth. State recommended
quantities of nitrogen, phosphorus, and potash nutrients and soil
amendments to be added to produce satisfactory topsoil.
D. Pre-Installation Conference: Conduct conference at Project site to comply with requirements
in Division 1 Section “Project Management and Coordination”.
PART 2 MATERIALS
2.1 TOPSOIL
A. Imported Topsoil:
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1. Loamy, friable soil, sterilized ASTM D 5268, pH range of 5.5 to 7, a
minimum of 4 percent dry weight organic material content; free of
stones 1/2 inch or larger in any dimension., free from subsoil,
refuse, roots, heavy or stiff clay, noxious seeds, sticks, brush, litter,
and other deleterious substances; suitable for the germination of
seeds and the support of vegetative growth.
2. Soil Texture: Loam soil with the following particle size distribution.
Approximate Particle Distribution Imported Topsoil
Gravel Less than 10%
Coarse to medium sand 30-65%
Fine sand 5-20%
Very fine sand 0-20%
Silt 15-25%
Clay 15-25%
2. Provide a minimum of one soil sample with the accompanying soil test report per 250
cubic yards of material required from samples obtained randomly throughout the source
field location or stockpile.
B. Existing Topsoil:
1. Existing topsoil may be used if it meets the requirements for imported topsoil or if
approved by the Landscape Architect. Provide a minimum of one soil sample with
accompanying soil test report for each topsoil type found at the site.
2. Supplement with imported or manufactured topsoil from off-site sources when
quantities are insufficient.
C. Topsoil shall not be stripped, transported, or graded if moisture content exceeds field
capacity or if the soil is frozen.
D. Topsoil stockpiles shall be protected from erosion and contamination.
E. Amendments required to be added as indicated on the soil test report shall be added by the
Contractor at the time of spreading and/or grading.
2.2 MATERIALS FOR SOIL AMENDMENT
A. Pine Bark: Horticultural-grade milled pine bark, with 80 percent of the material by volume
sized between 0.1 and 15.0 mm.
1. Pine bark shall be aged sufficiently to break down all woody material.
Pine bark shall be screened.
2. pH shall range between 4 and 7.0.
3. Submit manufacturer literature for approval.
B. Organic Matter: Commercially prepared compost; Leaf matter and yard waste composted
sufficiently to break down all woody fibers, seeds, and leaf structures, and free of toxic and
non-organic matter, pH range of 5.5 to 8. Submit 1 lb sample and supplier literature for ap-
proval..
1. Organic Matter Content: 50 to 60 percent of dry weight.
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C. Coarse Sand: Coarse concrete sand, ASTM C 33 Fine Aggregate, with a Fines Modulus
Index of 2.75 or greater.
1. Sands shall be clean, sharp, natural sands free of limestone, shale and slate particles.
2. Provide the following particle size distribution:
Sieve Percentage Passing:
3/8 inch 100%
No. 4 95-100%
No. 8 80-100%
No. 16 50-85%
No. 30 25-60%
No. 50 10-30%
No. 100 2-10%
D. Lime: Shall be ground, palletized, or pulverized lime manufactured to meet agricultural standards
and contain a maximum of 60 percent oxide (i.ecalcium oxide plus magnesium oxide). Submit
manufacturer literature for approval.
E. Sulfur: Shall be flowers of sulfur, palletized or granular sulfur, or iron sulfate. Submit
manufacturer literature for approval.
F. Fertilizer: Agricultural fertilizer of a formula indicated by the soil test. Fertilizers shall be organic,
slow-release compositions whenever applicable. Submit manufacturer literature for approval.
2.3 PLANTING MIX
A. Mixture of clay loam topsoil, course sand, and pine bark, mixed to the following proportion:
Component:
Pine bark 12%
Course sand and clay loam topsoil in quantities as necessary to achieve the particle distribution
criteria.
Approximate Finished Planting Mix Particle Distribution:
Gravel Less than 10%
Course to medium sand 55-65%
Fine to very fine sand 15-25%
Silt 10-20%
Clay 15-20%
B. Planting mix shall be thoroughly mixed, screened, and shredded.
C. Clay loam topsoil shall meet all the requirements of imported topsoil, except the particle size
distribution shall meet the USDA classification for clay loam.
D. Prior to beginning the mixing process, submit a 2-lb sample of the proposed mix with soil test
results that indicate the mix ratio and the results achieved.
E. During the mixing process but prior to installing the mix, submit a 2-lb sample for each 250 cubic
yards of planting mix, taken randomly from the finished soil mix, with soil test results for approval.
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In the event that the test results do not meet the required particle size distribution, remix and
resubmit a revised planting mix.
F. Make all amendments of lime/sulfur and fertilizer indicated by the soil test results at the time of
mixing.
G. All mixing shall take place in the Contractor’s yard, using commercial mixing equipment sufficient
to thoroughly mix all components uniformly.
H. Protect the planting mix from erosion prior to installation.
PART 3 EXECUTION
3.1 PREPARATION
A. Pre-Installation Conference: Conduct conference at Project Site to comply with requirements in
Division 1 Section “Project Management and Coordination”.
B. Protect structures, utilities, sidewalks, pavements, and other facilities, and lawns and existing
exterior plants from damage caused by grading operations.
C. Provide erosion-control measures to prevent erosion or displacement of soils and discharge of
soil-bearing water runoff or airborne dust to adjacent properties and walkways.
3.2 INSTALLATION OF TOPSOIL AND PLANTING MIX
A. Prior to the installation or modification of topsoil and planting mix, install subsurface drains,
irrigation main lines, lateral lines, and irrigation risers shown on the drawings.
B. The Landscape Architect shall review the preparation of subgrades prior to the installation or
modification of topsoil or planting mix.
C. Do not proceed with the installation of topsoil and planting mix until all utility work in the area has
been installed.
D. Protect adjacent walls, walks, and utilities from damage or staining by the soil. Use 1/2-inch
plywood and/or plastic sheeting as directed to cover existing concrete, metal, masonry work, and
other items as directed during the progress of the work.
1. Clean up any soil or dirt spilled on any paved surface at the end of each working day.
2. Any damage to the paving or architectural work caused by the soils installation contractor
shall be repaired by the general contractor at the soils installation contractor’s expense.
E. Till the subsoil into the bottom layer of topsoil or planting mix.
1. Loosen the soil of the subgrade to a depth of 2 to 3 inches with a rototiller or other suitable
device.
2. Spread a layer of the specified topsoil or planting mix 2 inches deep over the subgrade.
Thoroughly till the planting mix and the subgrade together.
3. Immediately install the remaining topsoil or planting mix in accordance with the following
specifications. Protect the tilled area from traffic. Do NOT allow the tilled subgrade to
become compacted.
4. In the event that the tilled area becomes compacted, till the area again prior to installing the
planting mix.
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F. Subsoiling: When subsoiling is indicated on the drawings, use a chisel plow subsoil ripping tool
mounted on a machine of sufficient power to make vertical trenches 18 inches deep into the
subsoil 24 inches apart. Run the ripping tool over each area in opposite directions so that each
area is ripped twice to thoroughly break up the compacted subgrade material prior to the
installation of topsoil and planting mix.
G. Install the remaining topsoil or planting mix in 8 to 10-inch lifts to the depths and grades shown on
the drawing. The depths and grades shown on the drawings are the final grades after soil
settlement and shrinkage of the organic material. The Contractor shall install the soil at a higher
level to anticipate this reduction of soil volume, depending on predicted settling properties for
each type of soil.
1. Phase the installation of the soil such that equipment does not have to travel over
already-installed topsoil or planting mixes.
2. Compact each lift sufficiently to reduce settling but not enough to prevent the movement of
water and feeder roots through the soil. The soil in each lift should feel firm to the foot in all
areas and make only slight heel prints. Over compaction shall be determined by the
following field percolation test.
a. Dig a hole 10 inches in diameter and 10 inches deep.
b. Fill the hole with water and let it drain completely. Immediately refill the hole with water,
and measure the rate of fall in the water level.
c. In the event that the water drains at a rate less than 1 inch per hour, till the soil to a depth
required to break the over-compaction.
3. Maintain moisture conditions within the soils during installation to allow for satisfactory
compaction. Suspend installation operations if the soil becomes wet. Do not place soils on
wet or frozen subgrade.
4. Provide adequate equipment to achieve consistent and uniform compaction of the soils. Use
the smallest equipment that can reasonably perform the task of spreading and compaction.
5. Add lime, sulfur, fertilizer, and other amendments during soil installation. Spread the
amendments over the top layer of soil and till into the top 4 inches of soil. Soil amendments
may be added at the same time that organic matter, when required, is added to the top layer
of soil.
6. Protect soil from over-compaction after placement. An area that becomes over-compacted
shall be tilled to a depth of 6 inches. Uneven or settled areas shall be filled and re-graded.
3.3 CLEANUP AND PROTECTION
A. During soil operations, keep adjacent pavings and construction clean and work area in an orderly
condition.
B. Protect exterior plants from damage due to landscape operations, operations by other contractors
and trades, and others. Maintain protection during installation and maintenance periods. Treat,
repair, or replace damaged exterior planting.
3.4 DISPOSAL
A. Disposal: Remove surplus soil and waste material, including excess subsoil, unsuitable soil,
trash, and debris, and legally dispose of them off Owner’s property.
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3.5 ACCEPTANCE
A. The Landscape Architect shall inspect all work for acceptance upon written request of the
Contractor. The request shall be received at least ten (10) calendar days before the anticipated
date of inspection.
B. Acceptance of soils shall be for general conformance to specified makeup, character, and quality
and shall not relieve the Contractor of responsibility for full conformance to the Contract
Documents.
C. Upon completion and re-inspection of all repairs or renewals necessary in the judgment of the
Landscape Architect, the Landscape Architect shall certify in writing that the work has been
accepted.
END OF SECTION