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    颗粒形状对粗粒土K0压缩特性影响的离散元分析

    Influence of particle shape on K0 consolidation characteristics of coarse-grained soils via DEM

    • 摘要: K0值是计算地基承载力、土坡稳定性和挡土墙土压力的关键参数。粗粒土往往具有形状不规则的特征,为研究其颗粒形状对粗粒土K0压缩特性的影响,首先采用离散元法生成5种不同形状的颗粒簇并获取其形状参数,之后取相同的颗粒粒径,以同样的方法分别生成相同初始状态的试样,最后进行K0压缩试验,就颗粒形状对粗粒土K0压缩特性的影响及其细观机理做了详细的探讨。研究结果表明:(1)不同形状试样的K0值均随法向应力的增长而降低,K0值与颗粒形状参数(纵横比、圆形度、完整度以及球形度)呈正相关,即颗粒越规则(形状参数趋于1),K0值越大。因此工程设计中应适当考虑颗粒形状的影响;(2)K0值与颗粒的配位数CN值有关,颗粒形状越不规则,CN值越大,K0越小;(3)K0值与试样平均接触力MF和强力链占比SP相关,颗粒形状的不规则将导致强力链占比和平均力减少,二者共同影响K0值的大小。研究成果可为现场K0值的评估提供理论参考,避免过度设计或设计不足,确保工程安全和经济性。

       

      Abstract: The K0 value is crucial for calculating the bearing capacity of foundations, the stability of slopes, and the earth pressure exerted by retaining walls. The particles in coarse-grained soil often have irregular shapes. To study the influence of particle shape on the K0 consolidation characteristics of coarse-grained soil, we used a discrete element method to generate five different particle cluster shapes and determine their shape parameters. Using the same particle size, we produced an initial state with the same method. Finally, we performed the K0 consolidation test to explore the impact of particle shape on the K0 consolidation characteristics and underlying mechanisms of coarse-grained soil. A comprehensive analysis was conducted on the impact of particle shape and the mechanisms involved. The results show that: (1) The K0 values of specimens with different shapes decrease as normal stress increases. The K0 value is positively correlated with the shape parameter of the particles; more regular particles (with a shape parameter closer to 1) have higher K0 values. Therefore, considering particle shape in engineering design is important; (2) The K0 value is related to the coordination number (CN) of the particles. More irregular particle shapes lead to higher CN values and lower K0 values. (3) The K0 value is connected to the average contact force (MF) and the ratio of strong chains to specimen SP. Irregular particle shapes reduce the ratio of strong chains and the average force, both influencing the K0 consolidation characteristics of coarsegrained soils. Such irregularities decrease the average force, affecting the K0 value. These findings can provide a theoretical basis for evaluating the K0 value in the field, helping to avoid over- or under-design and ensuring project safety and economy.

       

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