Study on strength characteristics of coarse-grained soil considering influence of mixing uniformity
In the existing research,coarse-grained soil is generally regarded as a homogeneous binary mixture,and the influence of of mixing uniformity between coarse and fine particles on its strength characteristics are ignored.Firstly,a quantitative index(Me)was proposed to describe mixing uniformity in coarse-grained soil.Secondly,through static triaxial tests,the inherent relationship between stress-strain curve,elastic modulus,failure strength and shear strength indicators and the Me were explored.Finally,based on the results of static triaxial tests,a modified Duncan-Chang model considering both confining pressure and Me effects was established,and its applicability and rationality were robustly verified.The results show that the stress-strain curve gradually transforms from strain-softening type to strain-hardening type with the increase of confining pressure.As Me decreases,it gradually develops into strain-softening type from strain-hardening type curve.When both confining pressure and Me increase,both elastic modulus and failure strength increase accordingly.The elastic modulus attenuates by 41.3%when Me decreases from 0.25 to 0,and the failure strength attenuates by more than 40%when Me decreases from 1 to 0.As Me gradually decreases,the overall skeleton-dense structure of the sample changes to the local skeleton-void structure and the local suspension-dense structure in different regions,which leads to gradual attenuation of cohesion and internal friction angle with decreasing Me.
road engineeringcoarse-grained soilmixing uniformitystrength characteristicsDuncan-Chang model
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