关键词: 城市生活垃圾土, 本构模型, 应力-应变关系, 三轴排水试验, 纤维加筋作用

Abstract: The composition of municipal solid waste (MSW) is very complex. A lot of fibrous materials in MSW, such as plastic, textile, leather and so on, make the mechanical properties of MSW obviously different from common clay and sand soil. It is difficult to simulate the mechanical behavior of MSW by the existed soil constitutive models. In this paper, the MSW is regarded as a combination composed of fibrous materials and paste, where paste is the residual components except for fibrous materials. The mechanical properties of MSW under the external load depend on the combined action of fibrous materials and paste. A concept of fibrous reinforcement effect parameter R is proposed in this paper. Through the development of plastic potential function considering the fibrous reinforcement, a new elasto-plastic constitutive model is established to simulate the stress-strain characteristics of MSW reasonably. The evolutionary equation of fibrous reinforcement effect parameter R is derived based on the test results. By comparing with the results of triaxial drained test and calculations of other constitutive models, it is found that the proposed model can perfectly reflect the stress-strain responses of MSW, especially for the upward curvature of MSW stress-strain responses at a larger strains level. As a result, the reasonability and effectiveness of this MSW constitutive model have been verified. The development of MSW constitutive model presents an important theoretical basis for better servicing landfill engineering projects.

Key words: municipal solid waste, constitutive model, stress-strain responses, triaxial drained tests, reinforcement effect of fibrous