Field Survey of Compressibility of Municipal Solid Waste

Abstract

This paper presents a study on the compressibility of municipal solid waste (MSW) by means of a field survey in Valdemingomez Landfill in Madrid, Spain. Organic matter content was 59%, there was no waste segregation and field compaction, nor internal drainage systems for gas and leachate. Solid waste management changed significantly since then in Madrid, but former characteristics of this landfill are similar to those of present inadequate MSW disposal sites in more than 60% Brazilian municipalities. Initially a geotechnical exploration of the landfill was carried out by mechanically drilled boreholes with Standard Penetration Tests, determination of in-situ density and moisture content, and geophysical methods. Subsequently, vertical and horizontal displacements caused by a surcharge load applied by a trial soil embankment were measured, as well as settlements due to biodegradation of the organic materials, for 19 months. Displacements were monitored by topographical references, inclinometer, continuous lines of settlement, and a sliding micrometer. Young’s modulus was estimated 1900 kN/m2 . Shear modulus increased from 7 to 31 MPa with depth according to results of spectral analysis of surface waves. The auscultation campaign indicated that primary settlements occurred during approximately 100 days and that accumulated secondary settlements amounted to 0.600 m, representing 55% of the total settlements.