Experimental investigations for assessing the influence of fly ash on the flow through porous media in Darcy regime

Abstract

Hydraulic Conductivity plays a vital role in the studies encompassing explorations on flow and porous media. The study investigates the compaction characteristics of river sand (Beas, Sutlej, and Ghaggar) fly ash mix in different proportions and evaluates four empirical equations for estimating hydraulic conductivity. Experiments show that an increase in the fly ash content results in a decrease in the Maximum Dry Density (MDD) and an increase in the corresponding Optimum Moisture Content (OMC) of sand-fly ash samples. MDD at optimum fly ash content was achieved at low water content, which resulted in lesser dry unit weight than that of typical conventional fill. In Beas, Sutlej, and Ghaggar sands the optimum fly ash content up to which the hydraulic conductivity value reduced uniformly was found to be 30, 45, and 40% respectively. Any further, increase in the fly ash content results in a negligible decrease in hydraulic conductivity value. The observed hydraulic conductivity of sand-fly ash mix lies in the range of silts, which emboldens the use of sand-fly ash mix as embankment material. Further, the evaluation of empirical equations considered in the study substantiates the efficacy of Terzaghi equation in estimating the hydraulic conductivity of river sand-fly ash mix. HIGHLIGHT In India, with the advancement in technology, we are being more focused on utilizing waste products for specific purposes. In the present study, flyash is a waste product that is used for making impermeable embankments, fills, and groynes. This study, provides a systematic approach i.e., how this waste product (flyash) being used for specific civil engineering purposes.

Initial Assessment on Hydraulic Conductivity of Rock Mass and its Size Effect Using Drilling Data

“…Predicting hydraulic conductivity and characterizing its size effect in a rock mass is fundamental to various geoscience and engineering disciplines, such as hydrogeology, energy, and environmental engineering (Kelly and Murdoch 2003; Zhang et al 2020; Chandel et al 2021). The hydraulic characteristics of a jointed rock mass are dominated by the joints, not the rock matrix (Guo et al 2015; Zheng et al 2020a); hence, the hydraulic conductivity of a jointed rock mass usually exhibits spatial variability and size effects (Zhang et al 2013; Chen et al 2018).…”

Assessment of Hydraulic Conductivity of Porous Media Using Empirical Relationships

“…It has a significant role, in estimating the quantity of seepage through earth dams and levees and conducting stability analysis of earth structures subjected to seepage forces [7]. Saturated K of porous media is important for modeling the flow of water in the saturated zone [8,9]. In the previous studies, it was postulated that the K of granular porous media is related to grain size characteristics i.e., d 10 , d 20 , d 50 , and d 60 [10].…”