Shear and compression behaviour of undegraded municipal solid waste
To ensure stability of a construction the physical properties of its components have tobe well known. In a landfill, waste presents the largest structural element and controlsboth the stability and integrity of the lining system. In spite of this critical role there is adearth of knowledge on behaviour of waste as an engineering material. Wastevariability and changes in waste stream aggravate the assessment of wastemechanical properties.In a literature review the main influences on shear behaviour of municipal solid waste(MSW) were identified. Design values and recommendation for shear parameter weresummarised. To assess mechanical behaviour in a systematic way the use of aclassification system was deemed crucial for a comparison of different findings fromliterature and a categorisation of waste in regard to its composition. A framework for aclassification system was introduced. Main elements of a comprehensive classificationsystem were identified in a literature review and discussed, and data from literaturewas applied to the classification framework. For the validation of a classificationsystem, municipal solid waste was examined in an in-situ waste sorting analysis andalso applied to the framework.The findings from the waste sorting and the classification system were also used todevelop a family of synthetic waste to gradually examine the influencing factors onwaste mechanical behaviour. For this, the materials, size ranges and shapes of wastecomponents identified in the waste sorting analysis were reduced to a minimum butstill representative amount. A range of synthetic waste compositions was engineeredand tested in a large-scale shear device. Compression tests were also conducted in alarge compression cell. The results from the laboratory testing were compared tovalues from the literature and MSW mechanical behaviour was subsequentlydiscussed in view to potential changes from changing waste streams.The results from shear and compression tests (constrained and shear modulus) onsynthetic waste were linked to the classification system and trends of the mechanicalbehaviour in relation to the tested synthetic waste compositions were identified.A framework for classifying MSW and comparing waste mechanical behaviour waspresented and demonstrated. A family of synthetic wastes was engineered and testedin shear and compression tests. The results were comparable to values from theliterature. Further research is recommended to refine the synthetic waste and theclassification.