Compression of peat soils

Thesis/Dissertation · Tue Jan 01 04:00:00 EST 1985

OSTI ID:5062202

Mochtar, N E

One-dimensional compression of peat is characterized using a simple rheological model in which the structural viscosity is assumed to be linear. This model utilizes three empirical parameters pertaining to the primary compression, secondary compression, and the rate of secondary compression. Based on the analysis of 43 laboratory and 10 field compression-time data, it is found that the primary and secondary compressibility parameters depend on the stress level and therefore can be determined in the laboratory. However, the values obtained in the laboratory tend to overestimate the field rate of compression and underestimate the magnitude of secondary compression. These parameters must be corrected for the effects of the non-linearity of peat behavior for accurate field prediction. Successful field predictions also require consideration of other important factors such as deviations from one-dimensional compression conditions, decomposition, vertical and lateral variability, and temperature effects. The compression behavior of precompressed peat under the final stress (reduced load) is affected by the amount of preloading ratio (ratio of the surcharge stress to the final stress). The magnitudes of primary, secondary, and tertiary compressibility parameters increase as the magnitude of the final stress increases relative to the surcharge stress while the viscosity of peat structure during secondary and tertiary compressions becomes smaller. The available criteria for selecting the surcharge stress application period developed for clay soils are not directly applicable to peat soils. A method to determine the compression parameters of peat using a constant rate of strain triaxial compression test is developed.

• Research Organization: Wisconsin Univ., Madison (USA)
• OSTI ID: 5062202
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
010600* -- Coal
Lignite
& Peat-- Properties & Composition
BENCH-SCALE EXPERIMENTS
COMPRESSION
DYNAMIC LOADS
ENERGY SOURCES
FIELD TESTS
FOSSIL FUELS
FUELS
MATERIALS TESTING
MATHEMATICAL MODELS
MEASURING METHODS
MECHANICAL TESTS
ORGANIC MATTER
PEAT
RHEOLOGY
STRAIN RATE
STRESSES
TESTING
VISCOSITY