Index properties and engineering properties of MSW with focus on shear strength of MSW By: Amir Jalehforoouzan Instructor: Prof.Dr.Erdal cokca Middle east technical university

To be presented  INTRODUCTION  What is the Municipal Solid Waste  SOURCE OF MUNICIPAL SOLID WASTE  TYPES OF MUNICIPAL SOLID WASTE  INDEX PROPERTIES  Soil Index Properties  Why do we need to assess Municipal Solid Waste Engineering Properties and Index properties?  Problems associated with determination of the Engineering Properties of MSW  ENGINEERING PROPERTIES OF MUNICIPAL SOLID WASTE  List of the important Engineering properties of MSW  Shear Strength of MSW  Problems associated with measurement Of MSW shear strength  QUESTION  References

 What is the Municipal Solid Waste Municipal solid waste (MSW),known as trash or garbage (US),refuse or rubbish (UK),is a waste type consisting everyday items discarded by public. The composition of municipal solid waste varies greatly form country to country and changes with time. In the past, most municipal waste was lanfilled, on the other hand, in most countries which have recycling culture, they are reused. Discarded plasic material, glass and paper are good examples for recyclable MSW. Fig.1 Fig.2  INTRODUCTION

 SOURCE OF MUNICIPAL SOLID WASTE Generally municipal solid waste is resulted from Community Commercial institutional recreational activities

 TYPES OF MUNICIPAL SOLID WASTE Municipal solid waste includes garbage rubbish ashes street cleanings dead animals medical waste and all other nonindustrial solid waste.

 INDEX PROPERTIES  Soil Index Properties Soil index properties are used extensively by engineers to discriminate between the different kinds of soil within a broad category. Water content Specific Gravity In-situ density Particle size distribution Consistency limits (Liquid Limit(LL),Plastic limit(PL),Shrinkage limit(SL)) Relative Density Unit weight of soils Activity of soils We can rely on our knowledge of the behavior of soil to engineer the disposal of waste.

 Why do we need to assess Municipal Solid Waste Engineering Properties and Index properties? It is not necessary and possible to recycle all kind of municipal solid waste. They can be landfilled and disposed in landfills despite efforts to minimize and divert waste. It is necessary to gain a better understanding of the properties of municipal solid waste to maximize the amount of waste that can be placed in existing and future landfills. By understanding of the properties of municipal solid waste, specially geotechnical properties, we can use overlying layers as construction foundations or etc. Therefore we need engineering properties of municipal solid waste.

 Problems associated with determination of the Engineering Properties of MSW Determination of the engineering properties of MSW is challenging due to The heterogeneity of the test material Subsequent variability in the measured data Lack of standardized testing apparatus

 ENGINEERING PROPERTIES OF MUNICIPAL SOLID WASTE Mechanical behavior of the waste body controls many aspects of landfill lining system design and performance, including stability issues and integrity of the geosynthetic and mineral lining components. Knowledge of the likely ranges of waste mechanical properties is required to assess potential modes of failure and hence to design the landfill engineering measures.

 List of the important Engineering properties of MSW Unit weight of MSW Compressibility Shear strength Lateral stiffness Horizontal in situ stress Hydraulic properties Permeability

 Shear Strength of MSW The shear strength parameters of soils or waste material are the most important parameters for assessing the stability of structures containing such materials. They may be determined in laboratory or in the field and by back-computions based on observed failure of structures. Hear strength of MSW is usually defined using the Coulomb failure criterion. The shear strength parameters that define the failure envelope are the slope of the failure envelop (Ø) and intercept on the y-axis (c) The intercept, c, can denote real cohesion between particles, but is often a function of one or more of the following: curvature of the failure envelope, variation between samples, measurement errors, or an indication of tensile strength. Therefore, it is common to define it as the ‘apparent cohesion’ or ‘cohesion intercept. Multiple factors including scaling/boundary effects and representative heterogeneity have made the laboratory determination of shear strength values of MSW challenging.

Mohr defined failure based on a critical combination of normal and shearing stress at failure on a failure plane

:major effective stress :minor principal stress

Above figure was suggested by Manasserto.Design values of C and Ø are defined according to three distinct zones

 Problems associated with measurement Of MSW shear strength It is both difficult and costly to obtain representative and hence reliable strength parameters of MSW. (due to large particle size, control of structure, heterogeneity, etc).Therefore it is preferable to obtain values from field studies. The most appropriate laboratory technique is direct shear test. The table below provides a summary of advantages and disadvantages associated with currently approaches for obtaining information on shear behavior of MSW.

QUESTION Please write common methods of measuring waste shear strength and explain advantages and disadvantages of them.(choose one of the methods to explain its advantages and disadvantages)

References [1] INVESTIGATION OF THE GEOTECHNICAL PROPERTIES OF MUNICIPAL SOLID WASTE AS A FUNCTION OF PLACEMENT CONDITIONS; by Wilson Win Yue Wong [2] GEOTECHNICAL PROPERTIES OF MUNICIPAL SOLID WAST; by SHAUN G.PELKEY [3] Development of a MSW classification system for the evaluation of mechanical properties; by Neil Dixon ¤, Ulrich Langer [4] Geotechnical of waste management ; by ISSA S.OWEIS, RAJ P.KHERA