Research On The Shear Mechanical Properties Of Rock-filled Concrete Construction Joints

The shear behavior of interface is one of the most significant behavior of Rock-filled Concrete(RFC)structures.The interaction between the exposed rock shear keys and the surrounding self-compacting concrete is the main resisting mechanism of the shear behavior of the RFC construction joints.Only accurate and reasonable prediction and assessment of the shear resistance mechanism of the construction joints can ensure the safety of the RFC structure.Through experiment research and meso-mechanical simulation,the influences of material properties of rock and concrete,as well as the geometrical characteristics on the shear behavior of the rock-filled concrete construction joints were studied.A shear force transfer model for rockfill concrete joints was developed based on the interface failure mechanism.And a designal method of shear bearing capacity was proposed to predict and evaluate the shear resistance of RFC joints.The main work and contribution of this paper include:1.24 small direct shear tests of rock-filled concrete construction joints were designed and conducted.The effects of rock shear keys properties and distribution on the shear performance of RFC joints were studied.Through the variation of rock characteristics and normal pressure,the effects of rock properties and stress states on the shear bearing capacity of construction joints were studied,which provided a data foundation for the meso-mechanical simulation and shear transfer model.2.Based on three-dimensional reconstruction,the three-dimensional(3D)nonlinear finite element(FE)meso-mechanical simulation of the shear behavior of RFC was carried out.According to the composition of RFC,a meso-mechanical modeling method based on 3D scanner was proposed,which considered the real shape of rockfill.The whole deformation process and strain distribution of construction joints were obtained.Based on the micromechanical model,numerical experiments of other parameters were carried out,which provided data support for the development of shear transfer model.3.A shear transfer model of RFC construction joints based on contact density was established.The model takes the material properties of rock and concrete as well as the distribution characteristics of rock as quantitative parameters.It can automatically select the failure mode according to the current stress state and accurately evaluate the shear performance of the RFC joint.The simplified shear capacity method provided a theoretical basis for the design and quality assessment of RFC.4.A series of large-size shear tests of the RFC construction joints on the real condition werecarried out.The shear performance of the RFC construction joints under composite force was explored.The applicability of the shear transfer model and the designal method of shear capacitywas verified by the experimental results.