| Because the earth rock dam, offshore platform, highways, high-speed rail, nuclear power station and high-rise buildings and other projects are under construction, the coarse soil is widely used in earth rock dam, bridge, highway and railway roadbed, the high fill and soft foundation treatment engineering, it as the main fill material, the mechanical properties of a crucial role on the normal use and safety engineering. The mechanical characteristics of coarse grained soil and the stress- strain relationship has become one of the important research topic in geotechnical engineering problems.Complex stress path and high stress, soil and foundation strength and stability problems will appear lower, while soil as elastic-plastic material strength and deformation is not only related to the stress state, but also its experience stress path dependent. For the same kind of soil, when using different loading methods and experimental methods of the shear failure, will have different stress change process, and the deformation characteristics of soil strength will also appear very big difference, therefore, through the study on the effect of soil stress change process on the mechanical properties, and then in the deformation analysis and the strength of soil stress history reflected in its condition has the extremely significant significance. The requirements of engineering design is the traditional soil mechanics cannot satisfy, thus forcing a number of scholars on the advanced numerical methods and advanced models to study thus replacing conventional experience method of calculation.This paper takes the coarse-grained soil as the research object, the consummation and the development of a fuzz y set hardening plasticit y model based on plastic theory. Different from the traditional elastic-plastic model the model, it provides a simple geometry to describe the stress strain characteristics of coarse grained soil, do not need to use analytic type such as kinematic hardening rule of complex, application is more easy to express and realize. And verify the validity of the model.Mainly includes the following several aspects of the work:1.The development of coarse grained soil hardening plasticit y constitutive model, the research explores different should stress- strain relationship of coarse grained soil under the stress conditions.2.The fuzz y set based on the theory of plasticity for Reid Bedford sand in conventional three axis compression of the tests data, using MATLAB programming software, using stress control algorithm, numerical simulation was carried out through the contrast found that mechanical properties of model material in this paper established fuzz y set plastic hardening model can better in the conventional three axial compression test, and further verified the correctness and effectiveness of the fuzz y sets of plastic hardening model.3.The establishment of the hardened plastic constitutive model for sensitivity analysis for the relevant model parameters. The main parameters of the model which includes: The shear modulus of elasticity G, The bulk modulus of elasticity K Fuzz y cone coefficient 0a and 1a; Plastic modulus parameters on the deviatoric stress space M and d; Dilatanc y function coefficient a; State parameters ψ etc. Wherein, elastic shear modulus, bulk modulus, elastic fuzz y cone coefficient, dilatancy function force on the space effect of stress- strain relationship of coarse grained soil.4.Using the validated coarse-grained soil hardening elastoplastic constitutive model, study the different stress paths should be coarse grained soil and the stress- strain relationship, and with the test data American in CASE data and results, choose Reid Bedford sand hollow cylinder torsional shear test results for comparison and correction, model can better simulate the coarse-grained soil materials, correctness and effectiveness and further verified hardening plasticity model.5.Finally, the main conclusions of this article, forwarding the conclusion relevant prospects. |
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