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.