波浪作用下斜坡上护面块体断裂破坏的数值模拟

Numerical simulation of failure of armour blocks on slope under wave action

基于FEM/DEM方法建立原型尺度数值模型,模拟波浪荷载作用下斜坡上护面块体内部的应力分布和断裂破坏过程。其中结构物所受的波浪力采用微幅波的理论解计算,块体之间的运动、接触以及块体变形采用FEM/DEM方法模拟。采用基于势函数的罚函数法计算块体之间的接触力,采用Single/Smeared破坏模型模拟混凝土块体开裂,采用中心差分法的显式积分算法进行数值求解计算。分别采用文中数值模型与ANSYS模型对自重作用下块体的应力进行比较分析,给出了块体碰撞破坏的两种形式,验证了数值模型应力和变形计算的精度。通过数值模拟给出了不同波浪荷载下斜坡上护面块体的运动、内部应力分布、裂缝形成和断裂过程,给出了不同点的应力历时曲线,探讨了块体的应力变化和断裂破坏的特性。

Based on FEM/DEM method, a prototype numerical model was presented to simulate internal stressdistribution, crack formation and fracture process of armor blocks on the slopes under wave action. The wave-in-duced hydrodynamic loads of the structures were calculated using the theoretical solution of the small amplitudewave. The armor blocks movement and contact between the armor blocks and the deformation of the blocks weresimulated using the FEM/DEM method. The contact force between blocks was calculated by the penalty functionmethod based on potential function. The combined single and smeared crack model was used to simulate the crackof concrete block. Numerical solution was calculated using the central difference explicit integration algorithm. Bythe application of numerical model and ANSYS model, the internal stress of concrete blocks under gravity were com-pared and analyzed. Two forms of collision failure of blocks were given. The calculation accuracy of stress and defor-mation of the numerical model was verified. The relative movement between armor blocks, the stress distributionwithin the blocks, crack formation and fracture process on the slopes under different wave loads were obtained fromnumerical calculation. The stress duration curves of different points were put forward. The properties of stress, crackformation and fracture process were discussed.