Effects of cross-section on infiltration and seepage in permeable stormwater channels

Factors affecting the infiltration rate have been studied fairly well by many researches; however, the effects of the cross-section of a permeable stormwater channel on the surface water depth reduction due to infiltration and seepage have largely been neglected. In the present study, towards improving the efficiency of permeable channels, the effects of the three components of a trapezoidal section, namely, the water depth, side slope, and base width, on the infiltration and unsteady seepage rates were investigated. Laboratory studies using models of the channel with unsaturated soil were performed under ponding condition using various initial water levels, base widths, and side slopes for two soil textures, namely, sandy loam and loamy sand. The results showed that the rate of surface water depth reduction by infiltration and seepage increases with increasing water level irrespective of the base width and side slope. In addition, an increase of the side slope increases the infiltration rate, with the effect becoming more significant with increasing initial water level, while the effect of varying the base width is insignificant

Effect of Different Binders on Settlement of Fibrous Peat

Peat commonly occurs as extremely soft, wet, unconsolidated surface deposits that are integral parts of wetland systems. The increasing growth of the population leads to the need to use peat land for development purposes. Cement is widely used for the stabilization of peat by the deep mixing method. This article describes a laboratory study on the effects of different additives on the settlement of fibrous peat. The effect of sodium silicate, ordinary Portland cement, and kaolinite on the settlement of treated peat by cementsodium silicate grout is investigated through a Rowe Cell consolidation test. At the end of this study, it is shown that increasing the amount of sodium silicate (within 2.5%), cement, and kaolinite in treated peat improves the settlement of fibrous peat much better than conventional binders like pure cement

Numerical Modelling of the Consolidation Behavior of Peat Soil Improved by Sand Columns

This paper presents a ground improvement method using sand as material in columnar inclusion. The main focus of the study is to model the consolidation behavior of peat soil reinforced by sand columns. The effects of sand column length and column diameter were determined using numerical analysis. It was revealed that the final settlement strongly depends on the area replacement ratio. The numerical results showed that the installation of larger-diameter, fully penetrated columns reduced soil settlement. The settlement reduction results of our numerical analysis are in good agreement with the experimental results. In order to improve the confining stresses of sand, an alternative approach utilizing geogrid encasement was examined numerically. The increasing stiffness of geogrid effectively increased the load carrying capacity of the sand column. Based on the results, geogrid performs better in smaller-diameter columns