Shear and Hydraulic Properties of Compost-Amended Topsoils for Use on Highway Slopes

Hydrologic and water quality modelling of bioretention columns in cold regions

“…HYDRUS 1D uses a Marquardt-Levenberg type of parameter optimization algorithm for inverse estimation of soil hydraulic, heat or solute transport parameters, and a maximum of 15 parameters can be calibrated at one time. In this study, the initial values of θ r , θ s , α, and n were referred to Carsel and Parrish (1988) (Duzgun et al, 2021). Due to the high deviation of each parameter (Carsel & Parrish, 1988) and uncertainties in the changes in soil properties caused by winter freeze-thaw cycles, this study tested a wide range of the five parameters.…”

“…The initial guess of K S was taken from Clapp and Hornberger (1978) whose average values of saturated conductivity were higher than Carsel and Parrish (1988)'s estimations, and the selection was based on the observation results in Li (2019) and Kratky (2019)'s experiments. Specifically, for the topsoil layer, the initial guesses of $$$ {\theta}_r $$$, $$$ {\theta}_s $$$, α , n , and K S of topsoil were all larger than those for the middle soil media layer because the compost added in topsoil increased effective friction angle, saturated hydraulic conductivity and water content (Duzgun et al, 2021). Due to the high deviation of each parameter (Carsel & Parrish, 1988) and uncertainties in the changes in soil properties caused by winter freeze–thaw cycles, this study tested a wide range of the five parameters.…”

Spatial Variation of Soil Properties: Foundation Design Challenges

“…Tests on amended soil materials showed that presence of organic matter increased the shrinkage resistance and shear strength of expansive clays [25], [27]. Direct shear and triaxial shear tests showed that compost addition resulted in an increase of effective friction angle in sands and noticeable increase in cohesion in clays [10]. This influence is depicted in Table IV.…”