砂土地基锚板基础抗拔承载力PFC数值分析

在模型试验的基础上,采用PFC离散单元法对条形锚板基础在中密砂土地基中的抗拔性能进行了数值分析。数值模拟采用簇颗粒单元来模拟砂粒的不规则形状,颗粒级配根据模型试验福建标准砂的级配按照相似级配法生成,细观参数根据数值双轴试验确定。水平锚板数值模拟结果与模型试验结果基本一致。与模型试验结果相比,颗粒流数值模拟能得到颗粒间接触力链的分布及其演化规律,能从细观角度来探明宏观抗拔承载力特性的演化机理。在此基础上对倾斜锚板上拔过程进行了模拟,分析了锚板前后砂粒的运动趋势以及接触力链的演化规律,并与已有承载力结果进行了对比分析。

PFC analysis of the uplift bearing capacity of plate anchors in sand

Based on some model tests,the PFC (Particle Flow Code) method was used to simulate the uplift behavior of the strip anchors in medium dense sand.Two shapes of clump particles were formed to simulate irregular sandy particles.The particle grading was generated using the similar grading method according to Fujian standard sand used in the model tests.Numerical biaxial tests were performed using a series of micro parameters.A set of micro parameters were picked out that the equivalent friction angle and dilation angle agreed with those of the sand in the model tests.Then the selected micro parameters were used to simulate the pullout process of plate anchor in the model test.The uplift resistance from numerical simulation agreed well with that from the model tests.Comparing with the model test,PFC method can provide the distribution and evolution process of the particle contact forces,thus can further provide a micro point of view to investigate the mechanism of uplift failure.Finally,the pullout process of inclined plate anchor in sand was simulated.The soil flow mechanism and the contact forces evolution laws of the particles around anchor were discussed.The ultimate pullout capacity of plate anchor by PFC simulations was also compared with previous results.