刚/柔性组合墙面加筋土挡墙内部破坏机制

Internal failure mechanism of reinforced soil walls with rigid/flexible facings

基于离心模型试验成果,建立软土地基刚/柔性组合墙面加筋土挡墙离散-连续耦合数值模型,采用离散单元颗粒流程序PFC和有限差分程序FLAC分别模拟加筋土挡墙和软土地基,分析挡墙的变形、筋材拉力分布及内部破坏演化过程,并与刚性地基上挡墙情况进行比较,以探讨刚/柔性组合墙面加筋土挡墙的内部破坏机制。研究结果表明,数值模型计算结果与离心模型试验结果吻合,其内部潜在破坏面经过连接件锚固端位置,各层筋材拉力均在连接件锚固端位置最大;软土地基上挡墙和刚性地基上挡墙的内部破坏面均一致,且筋材均由下而上依次断裂;软土地基上挡墙内部破坏面与地基圆弧滑移面贯通,为复合滑动模式,而刚性地基上挡墙整体破坏模式为折线型,连接件埋深范围内加筋体沿其底部连接件水平滑出。

A discontinuum and continuum coupling numerical model was built based on centrifuge modeling of a reinforced soil wall with rigid/flexible facings on soft soil. In the numerical model, the particle flow code（PFC） and the fast Lagrangian analysis code（FLAC） were used to simulate wall backfill and soft foundation, respectively. The deformation of the wall, the distribution of reinforcement loads along the wall height, and the internal failure evolution in the wall were simulated and analyzed. The internal failure evolution of the wall on rigid foundation was also simulated to compare with that of the wall on soft foundation. It was found that the numerical results are in good agreement with those measured in centrifuge modeling. The potential internal slip surface of the wall on the soft foundation passes through the end of the embedded anchors, and the tension in each reinforcement layer is the maximum at the end of the embedded anchors. The reinforcements in the walls are on either soft or rigid foundation break at the end of the anchors from the bottom to the top in their limit states. The walls on soft foundation fail in a plane slip passing through the end of the anchors intersecting the circular plane slip in soft foundation. However, the walls on rigid foundation slide horizontally along the bottom anchors with a plane slip at the end of the anchors.