摘要
结构性黄土的力学性能、工程特性与重塑土有显著区别,特别是在高应力作用下黄土的结构性对抗剪强度的发挥有显著影响。因此基于陕北某高填方工程黄土地基,对原状黄土与重塑黄土进行了室内高围压固结排水三轴试验。通过分析原状与重塑黄土的应力应变曲线和偏应力差值曲线,研究了结构性黄土的强度变化机理,结果表明黄土在低围压下结构性强度迅速发挥,并随着围压的增大、胶结物质持续破坏,内摩阻力发挥开始逐渐增强;基于结构性岩土材料破损机理的二元介质模型,通过引入抗剪贡献率ξv,修正并建立了高应力下结构性黄土的抗剪强度准则;并与试验结果进行对比,表明该强度准则能够一定程度上反映出结构性黄土在不同围压作用下粘聚分量与摩擦分量分步发挥的内在机理。
The mechanical properties and geotechnical characteristics of structured loess and reconstituted loess are distinct in many aspects,especially the play of shear strength will be affected by loess structure characters under high stress.Therefore,based on a loess foundation of a high-fill project in northern Shaanxi,the consolidated drainage three-axis test of undisturbed loess and reconstituted loess under high confining pressure was carried out. And the strength behavior and mechanisms of structured soils were analyzed from the stress-strain curves and partial stress differential curve of undisturbed loess and reconstituted loess. The results show that the structural strength of loess is rapidly exerted under low pressure,then the internal friction begins to gradually develop with increasing confining pressure and the decomposing cementing substance; based on the geo-binary medium model considering the fracture mechanism of geomaterials,the strength criterion for structured loess under high stress is modified and established by introducing the parameter of shear resistance contribution ratio ξv. By comparisons of predictions with experimental data, it was demonstrated that the modified shear strength criterion could reflect the inherent playing mechanism of the cohesive component and friction component under different confining pressures.
作者
郅彬
王永鑫
邓博团
刘伟
ZHI Bin;WANG Yong-xin;DENG Bo-tuan;LIU Wei(College of Architecture and Civil Engineering,Xi＇an University of Science and Technology,Xi＇an 710054,China;China Electronic Research Institute of Engineering Investigation and Design,Xi＇an 710054,China)
出处
《煤炭工程》
北大核心
2018年第10期41-45,共5页
Coal Engineering
基金
陕西省重点研发计划项目(2018SF-397)
陕西省教育厅专项科研计划项目(16JK1513)
关键词
黄土
结构性
高应力
抗剪强度
二元介质模型
loess
structured
high stress
shear strength
geo-binary medium model
