Evaluating elastic wave velocities in Brazilian municipal solid waste

Abstract

The sanitary landfills in Brazil are, generally, characterized by their high organic material content (around 60%), presence of different types of mixed wastes, and low compaction energy, which differentiates them from the landfills of developed and high-income countries. To prevent environmental and slope stability risks, it is crucial to understand the behavior of such landfills and the changes in their physical properties over time. The compression wave velocity (V p ) and shear wave velocity (V s ) are important parameters to subsidize the mechanical characterization of sanitary landfills, using which can be derived the dynamic elastic properties of municipal solid waste (MSW) for stability analysis. Using the geophysical methods of seismic refraction, active and passive multichannel analysis of surface waves, and crosshole test, it was obtained the values of Vp and Vs by employing an experimental cell and a lysimeter filled with MSW in the City of Campinas, São Paulo State, Brazil. The results obtained from the crosshole test showed that Vp ranged from 217 to 252 m/s and Vs ranged from 86 to 89 m/s. These low values can be attributed to the high content of organic material, low compaction energy, and climatic conditions such as high pluviometry index and high temperatures that together lead to changes in the pore fluid saturation, effective stress, and pore pressure. These values are indicative of the lower limit of the corresponding velocities reported in most literature; however, they are in accordance with the values reported for landfills located in countries with similar socioeconomic and climatic conditions.

An overview of in situ testing and geophysical methods to investigate municipal solid waste landfills

“…Atypical high V s observed near the surface were possibly due to cover soil or other stiff material (Zekkos et al 2014 ; Ramaiah and Ramana 2017 ). These trends may explain the relatively low velocities measured at landfills with poor compaction and thin cover soil layer (Abreu et al 2016 ; Aranda et al 2019 ).…”

A case study on establishing the state of decomposition of municipal solid waste in a bioreactor landfill in India

“…In the previous studies, V s value has been reported ≈83-220 ms −1 for Cozzo Vuturo landfill, Italy (Castelli et al, 2017) and 70-200 ms −1 for different landfills in southeast Michigan such as Arbor Hills Oakland Heights landfill, Carleton Farms landfill and Sauk Trail Hills landfills (Zekkos et al, 2014). Aranda et al (2019) have compiled results of shear wave velocity of MSW in landfills available in the literature and reported that V s varies widely from 50 to 400 ms −1 . However, for the landfill at City of Campinas in São Paulo State, Brazil, the V s value (=86-89 ms −1 ) is found to be lower, which is attributed to the less compaction, high OM in MSW and extreme climatic conditions (viz.…”

“…However, for the landfill at City of Campinas in São Paulo State, Brazil, the V s value (=86-89 ms −1 ) is found to be lower, which is attributed to the less compaction, high OM in MSW and extreme climatic conditions (viz. high pluviometry index and high temperature) (Aranda et al, 2019). Furthermore, a comparison of the literature data (Anbazhagan et al, 2016;Haker et al, 1997;Zekkos et al, 2014) (refer to Supplemental Table S3) has been conducted as depicted in Figure 11(b), and it can be observed that in general V s tends to increase with depth.…”

“…In this context, researchers have employed: (i) non-destructive tests (NDTs) such as multichannel analysis of surface waves (MASW), standard penetration test, cone penetration test (CPT), dilatometer Marchetti test and electrical resistivity tomography and (ii) destructive tests (DTs), to investigate the condition of the MSW in the landfills (Anbazhagan et al, 2016;Aranda et al, 2019;Castelli and Maugeri, 2014;Castelli et al, 2017;Di Maio et al, 2018;Dumont et al, 2017;Elk et al, 2014;Gomes et al, 2013;Koda et al, 2017;Machado et al, 2010;McKnight et al, 2015;Ramaiah et al, 2016Ramaiah et al, , 2017Vilar and Carvalhod, 2004;Yang et al, 2019;Zekkos et al, 2014;Zhan et al, 2008). However, a critical synthesis of data reported by these researchers reveals that both NDTs and DTs have their strengths and limitations, and should be employed very carefully.…”

Support method for interpretation of regional groundwater monitoring in urban areas

“…Similarly, cities modify the heat flow and, consequently, water evaporation processes and rain patterns. Equally important, various urban activities transfer immense amounts of matter from the atmosphere (Babinski et al 2003(Babinski et al , 2012 and from the surface to the soil (CETESB 2013, Santos Filho et al 2017, Aranda et al 2019, rivers (Porto 2003, Xu et al 2019, and aquifers (Foster and Hirata 1988, DAEE 2012, Cary et al 2013, Conicelli 2014, Petelet-Giraud et al 2018, sometimes contaminating them. In this urban cycle of water, energy, and matter, one of the rarely researched components is the aquifer (Foster et al 2011, Hibbs and Sharp 2012, Hirata and Suhogusoff 2019, even in countries in Europe and North America.…”