延安新区压实Q_2黄土增减湿高压压缩变形特性

Moistening or Demoistening Compression Deformation Characteristics of Compacted Q_2 Loess under High Pressure in Yan'an New District

为研究压实Q2黄土在高压力条件下的增减湿高压压缩变形特性,采用DGD系列型高压固结仪分别对不同初始压实度和不同初始含水率条件下的压实Q2黄土试样进行高压压缩试验,分析压实Q2黄土压缩变形特性随初始压实度和初始含水率的变化规律;运用不同方法对压缩试验成果进行整理,分析侧限条件下压实Q2黄土应力应变关系特点。结果表明:压实Q2黄土的压缩变形特性受初始压实度和初始含水率的影响较大,在最大压实度和最优含水率处的压缩变形量最小;初始压实度不同,拟合压实Q2黄土应力应变关系曲线的函数也不同,在较低初始压实度条件下,用双曲线拟合效果较好,此时割线模量与应力呈线性关系,在较高初始压实度条件下,用幂函数拟合效果更好。

Focused on the study on moistening or demoistening compression deformation characteristics of compacted Q2 loessunder high pressure, several one-dimensional oedometer tests are conducted with GDG high pressure odometer to study the influenceof initial compaction degree and initial moisture content on the compression deformation characteristics. Meanwhile, several differentmethods are employed to process the test data, analyzing the stress-strain behavior of compacted Q2 loess under high pressure. The resultsof the study suggest that the initial compaction degree and initial moisture content have a great influence on the compression deformationcharacteristics of compacted Q2 loess. With the increase of the compaction degree, the amount of compression deformation decreasesrapidly in the same moisture condition. When in the same degree of compaction, the minimum amount of compression deformation isachieved just in the optimum water content. Furthermore, the stress-strain behavior of compacted Q~ loess is greatly influenced by theinitial compaction degree under high pressure. In the condition of low compaction degree, its stress-strain curve is greatly fitted by thehyperbolic function. However, it is more practical to apply power function to it under high compaction degree.