OBJECTIVES

• Determination of mechanical properties of different types of municipal solid waste
• Investigation of basic mechanisms, the mechanical behavior is due to
• Identification of material parameter affecting the mechanical properties
• Development of appropriate calculation methods

METHOD

• Development of a new bearing model for MSW considering its ability to incorporate tensile forces backing the shear strength (so called fibres cohesion)
• Design of a new testing device: the tension test under normal load

Tension test under normal load: testing procedure
above: testing device after loading
below: testing device durcing tension test

RESULTS

• Shear strength is dominated by fibers
• The portion of shear strength due to fiber effects is called fibrous cohesion
• Fibrous cohesion shows linear relation to normal stress (vertical to main fiber direction)
• Shear strength of MSW can amount to normal stress (equvalent to phi = 45 degree!)
• Fibrous cohesion can be implemented in analytical calculation methods
• New calculation methods allow steeper slopes but also gives realistic limits for stability

Approach for new calculation method: Goettingen-Deiderode, landfill mining project
Construction of a 75 degree steep slope ton save mining works (300.000 cubic meters)

REFERENCES

Koelsch (1995): Material values for some mechanical properties of domestic waste. CISA (eds.): Proceedings of the Fifth International Landfill Symposium, Vol. 2, Cagliari (Italy). Download

Koelsch, Ziehmann (2004): Landfill stability – risks and challenges. Waste Management World, issue Mai/June, ISWA, Copenhagen. Download

Several German publications available