动力及湿化作用下粗粒土路堤填料的力学性能

Mechanical properties of coarse-grained soil embankment filling under dynamic load and humidification

为研究粗粒土路堤填料在动力湿化作用下的力学性能,结合动、静三轴试验探讨不同动力和湿化条件下粗粒土试件的轴向永久变形特性,分析不同动偏应力σ_(d)、含水率ω及荷载频率f影响下粗粒土路堤填料的力学和变形特性。试验结果表明:粗粒土路堤填料的轴向永久变形随着动偏应力σ_(d)、土体含水率ω、荷载频率f的增加而增大,但轴向永久变形主要发生在动力加载前期,当加载次数达到1000次时,各试件的轴向永久变形达到总变形的83%以上,之后轴向永久变形趋于稳定;粗粒土路堤填料试件在静三轴压缩试验中的应力应变关系表现出明显的非线性,动偏应力σ_(d)、土体含水率ω、荷载频率f越高,试件在静三轴试验中达到同一轴向应变所对应的偏应力越低;在不同动力及湿化条件下,粗粒土路堤填料试件的黏聚力c和内摩擦角ϕ均随动偏应力σ_(d)、含水率ω、荷载频率f的增加而降低,而其体应变ε_(v)则相反。

In order to study the change law of the mechanical properties of the coarse-grained soil under the dynamic load of the embankment,the dynamic and static triaxial tests were combined to explore the axial permanent deformation characteristics of the coarse-grained soil specimens under different dynamic and humid conditions.The mechanical properties and deformation characteristics of the embankment such as stress-strain relationship and strength characteristics filled with coarse-grained soil under different dynamic loads,moisture contents and load frequency conditions were analyzed.The results show that the axial permanent deformation of coarse-grained soil filled by embankment increases with the increase of dynamic deviator stress σ_(d),soil moisture contentωand load frequency f,but the axial permanent deformation mainly occurs in the early stage of dynamic loading.When the loading times reaches 1000 times,the axial permanent deformation of each specimen reaches more than 83%of the total deformation,and the growth rate gradually decreases,the axial permanent deformation curve tends to be flat.The stress-strain relationship of the embankment filled coarse-grained soil specimen in the static triaxial compression test shows obvious nonlinearity.The higher the dynamic deviator stress σ_(d),soil moisture contentωand load frequency f,the lower the deviator stress corresponding to the same axial strain.Under different dynamics and humidification conditions,the cohesion c and internal friction angle ϕ of the specimens filled with coarse-grained soil on the embankment all decrease with the increase of dynamic deviator stress σ_(d),water contentωand load frequency f,while the volume strainεv is opposite.