基于大型三轴排水剪切试验的粗粒土强度特性研究

鉴于粗粒土强度受内外因影响往往随时间和空间而变化,选取塔城砂砾石试样做了大型三轴试验,研究了轴对称应力条件下粗粒土的强度特性。结果表明,体变增量为零对应于屈服强度,此时体缩变形达最大值;体变增量与轴向应变增量之比的最小值与破坏强度相对应,此时剪胀性最大;破坏强度一般比屈服强度大,且应力应变曲线软化特征越强,破坏强度与屈服强度之间的差异越大;屈服强度参数粘聚力小于破坏强度参数粘聚力,但屈服强度参数内摩擦角大于破坏强度参数内摩擦角。

Strength Behavior of Coarse-grained Soils Based on Large-scale Triaxial Drained Shear Test

The strength behavior of coarse-grained soils is influenced by internal factor and external factor, which are usually changed with time and space. Large-scale triaxial tests of Tacheng sand-gravel were conducted in order to investigate strength behaviors. The test results show that the yield strength and the maximum volume shrinkage deformation occur when the volumetric strain increment is zero; the failure strength and the maximum dilatancy reach at the minimum ratio of volume strain increment to axial strain increment; the failure strength is usually larger than yield strength, and the difference between failure strength and yield strength increases with the enhancing of stress softening behavior; the cohesive force of yield strength is smaller than the cohesive force of failure strength, but the internal friction angle of yield strength is larger than the internal friction angle of failure strength.