Characterizing a Brazilian sanitary landfill using geophysical seismic techniques

Area of Science:

• Geophysics
• Geotechnical Engineering
• Environmental Science

Background:

• Municipal Solid Waste (MSW) characterization is crucial for understanding its mechanical behavior and environmental impact.
• Humid, subtropical climates present unique challenges for landfill management due to high moisture content and potential leachate issues.

Purpose of the Study:

• To investigate the mechanical response of buried municipal solid waste using geophysical techniques.
• To determine the influence of depth, moisture content, and operational history on waste properties.
• To differentiate waste strata based on geophysical and direct investigation data.

Main Methods:

• Application of crosshole and multichannel analysis of surface waves (MASW) seismic techniques.
• Direct investigations including waste composition analysis, moisture content, unit weight, and temperature measurements.
• Correlation of geophysical data (shear wave velocity - VS, compression wave velocity - VP) with direct investigation findings.

Main Results:

• Shear wave velocities (VS) ranged from 92 to 214 m/s and compression wave velocities (VP) from 197 to 451 m/s, increasing with depth.
• MASW-derived VS values were lower than crosshole-derived VS values, attributed to frequency differences.
• Waste body divided into two strata: a poorly drained lower stratum with high moisture and a better-drained upper stratum.

Conclusions:

• Geophysical methods effectively characterize the heterogeneous nature of MSW.
• Waste strata exhibit distinct mechanical properties influenced by moisture content and operational history.
• Findings provide a lower bound for geophysical parameters in low-compaction waste, informing landfill design and management.