At-Rest Lateral Pressure of Peat Soils

The results are presented of an experimental program directed toward evaluating K₀ (the coefficient of lateral earth pressure under conditions of no lateral formation) and its dependence on stress history and other parameters of peat soils. Three peats with different fiber contents were consolidated in a custom-built K₀-test tube. During loading and rebound, the axial deformations, pore pressure, and both axial and radial stresses were measured. A sand and clay sample compared well with previously reported values and empirical predictions. The values of K₀ for the peat sample were found to remain essentially constant during the loading phase, but their values (which increased gradually during unloading) never exceeded unity. Several indirect approaches were tried to compute the K₀ of the peats from effective shear strength parameters. Peat type appeared to exert a significant influence on the measured values of K₀ during loading.