Effect of Compaction on Soil Physical Properties of Differently Textured Landfill Liner Materials

Abstract

Mineral landfill liners require legally-fixed standards including a sufficiently-high available water capacity (AWC) and relatively low saturated hydraulic conductivity values (Ks). For testing locally available and potentially suitable materials with respect to these requirements, the soil hydraulic properties of boulder marl (bm) and marsh clay (mc) were investigated considering a defined compaction according to Proctor densities. Both materials were pre-compacted in 20 soil cores (100 cm3) each on the basis of the Proctor test results at five degrees of compaction (bm1–bm5; mc1–mc5) ranging between 1.67–2.07 g/cm3 for bm and 1.09–1.34 g/cm3 for mc. Additionally, unimodal and bimodal models were used to fit the soil water retention curve near saturation and changes in the pore size distribution (PSD). The structural peak of the PSD in the fraction of pore volume between −30 and −60 hPa was more pronounced on the dry side (bm1–2, mc1–2) than on the wet side of the Proctor curve (bm4–5, mc4–5). Therefore, the loss in structural pores can be attributed to an increasing dry bulk density for bm and an increasing gravimetric moisture content during Proctor test for mc. While the mc fulfils the legal standards with AWC values between 0.244–0.271 cm3/cm3, the Ks values for bm between 1.6 × 10−6 m/s and 3.8 × 10−7 m/s and for mc between 7.4 × 10−7 m/s and 1.2 × 10−7 m/s were up to two orders of magnitude higher than required. These results suggest that the suitability of both materials as landfill liner is restricted.

Using Geomembrane Liners to Reduce Seepage through the Base of Tailings Ponds—A Review and a Framework for Design Guidelines

“…More research is needed, for example on the functionality of geomembrane liners and the underliner and overliner soil, and on related solutions and how the combined operation of natural soil and artificial liners can be optimized through the use of a constructed layer of natural soil or bentonite liners. Some studies, e.g., [14,23,44,81,103] have expressed concerns about the long-term behavior of clay liners and layers, which are not believed to be as reliable in composite structures as the calculations suggest. Changes in the behavior of clay in the long run cannot be taken into account in calculations, e.g., channels, fissures, or other weaknesses that allow leakage may form.…”

Hydraulic and Swell–Shrink Characteristics of Clay and Recycled Zeolite Mixtures for Liner Construction in Sustainable Waste Landfill

“…The samples prepared for molding gravimetric water content determination are also presented in Figure 2. Distilled water was used as a permeating liquid, based on numerous studies concerning applicability of various mineral materials for compacted liner construction [18,20,22,[24][25][26][27]29,[32][33][34]. The obtained values of saturated hydraulic conductivity coefficients were subjected to the standard statistical procedures including Shapiro-Wilk normality tests and comparison of two dependent variables (Ks for clay-zeolite mixtures and reference samples) by nonparametric Wilcoxon test (due to observed distributions being different than normal).…”

“…As it was previously reported [18][19][20][21][22] locally available clays are often suitable for compacted clay liner construction, mainly compacted wet of optimum (on wet side) of the Proctor curve, forming water content greater than the plastic limit [23]. However, in some cases, the local clay substrates may not allow reaching the required values of K s in the full range of molding water contents [24] or for the selected values of initial water content, usually after compaction dry from optimum (dry side of the Proctor curve) [18,20]. However, the insufficient sealing capabilities of some locally available earthen materials may be improved by addition of the available, sustainable, and recycled fine particles specimens such as various types of zeolites, silica fume, lime [25], bentonites, fly ash, coal gangue [26], construction and demolition waste, activated carbon, shale [27], olivine [28], organoclays, etc.…”

Umidade ótima do solo para fins de disposição de resíduos sólidos urbanos

“…Diante da relevância do tema, diversas pesquisas referem-se à umidade ótima em áreas de aterros sanitários, seja em camadas de base ou de cobertura final (NIK DAUD; MUHAMED; KUNDRIRI, 2017; BECK-BROICHSITTER; GERKE, HORN, 2018;COSTA et al, 2018;SOBREIRA et al, 2008;ARIFIN, 2019;BECK-BROICHSITTER, GERKE. HORN, 2019;EMMANUEL et al, 2020;DALA SANTA et al, 2020).…”