PROJ00414

• Contract/PO #: C153326
• Contractor Name: Fruitland Mesa Water Conservancy District
• Contract Type: Grant
• Water District: 0
• County: Montrose
• Bill Number: XB 99-999
• Loan Projects - Doc Type: Feasibility Study

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Laboratory Testing

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The laboratory testing program was directed toward determining the

engineering properties of the borrow area soils sampled on property

belonging to F.M.C.D. for the proposed expansion of Gould Reservoir

Dam and dike. The composite soil samples were first classified

according to the Unified Soil Classification (U.S.C.) system based on

visual evaluations, natural water content determinations, and liquid

and plastic limit tests. Three representative samples, two from

Borrow Area A and one from Borrow Area B, were then selected for

determination of engineering properties to be used in design. The

tests performed on each sample were: Standard Proctor Compaction test

(ASTM D698-70A), Hydrometer Grain-size Analysis, pin-hole Dispersion

test, and shear strength tests. The sunnnary of test results is

presented in Figure 8.

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Classification

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The soils tested are moderately to highly plastic silty clays with
less than 4 percent coarser than clay and silt size. According to the
U.S.C., they are CL lJ.nd borderline to being CH soils; liquid limits
range from 31 to 54 percent and plasticity indices range between 13 to
34 percent; the average values are 44 and 25 percent, respectively.
Natural moisture contents are generally about 5 percent wet of the
plastic limit. (See Summary on Figure 8.)

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Standard Proctor Compaction

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Two Standard Proctor Compaction tests were performed on composite

samples obtained from Borrow Area A. The materials are generally

alike with a maximum dry density of about 103 1bs/ft3 and an optimum

moisture content of 21 percent. A third test was performed on a

Borrow Area B sample, maximum dry density was 109 1bs/ft3 at an

optimum moisture content of 17 percent. These values are used for

sample preparation in the Pin-hole Dispersion and Triaxial Strength

Tests. The three compaction curves are presented on Figures 9 through

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11.

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