初始相对密实度对砂土强度特性影响的试验

针对两种级配不同的福建标准干砂,在不同固结压力下进行常规三轴试验,着重探讨不同初始相对密实度对砂土抗剪强度的影响.试验结果表明:考虑砂土的初始结构性,即初始相对密实度不同时,砂土的强度特性会发生较为显著的变化.相同试验围压下,随着密实度的增加,试样的初始切线模量有所增长、试样的峰值偏应力逐渐增大;而相同密实度的情况下,随着试验围压的增加,初始切线模量也有较为显著的增长、试样的峰值偏应力也逐渐增大;试样的内摩擦角随着初始相对密实度的增加基本呈线性增长.结合试验结果建立了砂土抗剪强度指标与初始相对密实度之间的关系,进而考虑初始相对密实度对莫尔-库伦准则进行修正.

Experiment of initial relative density effects on sand strength

Conventional triaxial experiments of two kinds of Fujian standard sands with different gradation were performed at different confining pressure.The effects of initial relative density on shear behaviors of sand were investigated.The experimental results indicate that the initial structure has a considerable effect on shear strength of sand.At the same confining pressure,the initial tangent modulus and the peak deviator stress increase with the increasing of initial relative density.For the same relative density,the initial tangent modulus has a significant growth with the increasing of confining pressure,while the peak deviator stress increases gradually.The internal friction angle of the sample shows a linear growth with the increase of the initial relative density.Combined with the test results,the relationship of shear strength parameter and initial relative density was established to modify Mohr-Coulomb criterion with considering initial relative density.