水泥固化砂土抗力机制精细离散元数值研究

FINE DISCRETE ELEMENT SIMULATION ON THE RESISTANCE MECHANISM OF CEMENT-STABILIZED SAND

  • 摘要: 胶结接触界面的力学行为对水泥固化有机质浸染砂强度的影响极为重要。结合考虑抗转动因素的新平行胶结模型,提出了“两种单元、三类接触、五组承力”的精细离散元模拟模式,对水泥固化有机质浸染砂的无侧限抗压强度试验和静三轴试验进行模拟再现,揭示了熟石灰提高水泥固化有机质浸染砂强度的接触界面力学机制,明确了不同加载条件下水泥固化有机质浸染砂界面破损行为的发展机制。结果表明:熟石灰的加入可以改善砂颗粒与砂颗粒的接触界面、砂颗粒与胶结料的胶结界面,提高接触界面的摩擦力、胶结界面的黏聚力,从而使其强度得以提高;有侧向约束时,胶结接触持续破坏,颗粒组分之间相对滑移、旋转运动加剧,砂颗粒-砂颗粒间的摩擦承力增大。

     

    Abstract: The mechanical behavior on the cementation interface is extremely important to the strength of cement-stabilized organic-matter-disseminated sand (OMDS). While a new parallel cementation model with the respect of the anti-rotation factor is used, a fine discrete element simulation model, which is called “two elements, three types of contact, and five groups of bearing forces”, is proposed. Through simulation of the unconfined compressive strength test and static triaxial test of cement-stabilized OMDS, the interfacial mechanical mechanism of enhanced strength is revealed. The development mechanism of interface damage behavior under different loading conditions is clarified. The results show that the hydrated lime can improve the contact interface between sand particles and sand particles, the cementation interface between sand particles and cemented particles. And then the friction and cohesion of the contact interface can be increased to enhance the strength of cement-stabilized OMDS. On the condition of lateral constraint, the bonded contact continues to be destroyed, while the relative slip and rotation between particle components are intensified and the friction between sand particles increases.

     

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