饱和砂土液化过程中细观组构的模型试验研究

Model Testing of Meso-fabric of Saturated Sand Liquefaction

采用室内振动台模型试验对液化过程中饱和砂土颗粒的细观组构进行研究.分析了砂土颗粒在液化破坏过程中颗粒长轴方向、平均配位数、孔隙率的演化规律及其与宏观现象之间的联系.应用表征上述量的组构参数分析了砂土的诱发各向异性,指出在循环荷载的作用下,砂土颗粒不断重新排列定向以适应新的应力状态,导致累积配位数的丧失、孔隙率增大,继而导致液化的发生.研究成果对于揭示砂土变形(液化)的细观机理以及建立砂土的细观力学模型都具有重要意义.

Based on the shaking table model testing, the meso- fabric characteristics of saturated sand are studied including macro-axis orientation for sand granules,average coordination numbers and porosity. Induced anisotropy of sand is analyzed by fabric features. The results show that under cyclic loading, sand granules continuousIy rearrange and redirect for the new stress state which results in decreasing cumulative coordination numbers and increasing porosity, and then liquefaction. The study is expected to contribute to disclosing the meso-mechanism of sand liquefaction relating to the mesofabric and macro mechanical response of granular soils and developing meso-mechanical models of granular media.