道砟模型精度对离散元模拟结果的影响

Influence of Ballast Model Accuracy on Discrete Element Simulations

基于-20℃低温条件下冻结道砟单轴压缩试验,探究不同精度道砟模型对单轴压缩试验的离散元模拟结果的影响。采用离散元法建立了精度相对较高的道砟模型,并根据单轴压缩试验结果标定了道砟颗粒间的细观接触参数。在此基础上,构建不同精度的道砟颗粒模型并进行单轴压缩试验模拟,讨论模型精度对模拟结果的影响。研究结果表明:①冻结道砟试样的弹性模量和抗压强度随模型精度的下降而减小;②道砟颗粒的位移、黏结键的数量及破坏率均随道砟模型精度的下降而减小;③道砟颗粒间接触力随模型精度的下降总体上呈减小趋势,但随着模型精度的提高,颗粒间接触力传递和力链的分布更均匀。

Based on the uniaxial compression test of frozen ballast under-20°C condition,the influence of dif⁃ferent accuracy ballast models on the discrete element simulation result of the uniaxial compression test was in⁃vestigated.A higher accuracy ballast model was established using the discrete element method,and the meso⁃scopic parameters between the ballast particles were calibrated according to the uniaxial compression test re⁃sult.Then,different accuracy ballast models were constructed,and uniaxial compression test simulations were conducted to study the influence of ballast model accuracy on the simulation result.The research results show that the elastic modulus and compressive strength of the frozen ballast specimens are reduced with the model accuracy decreasing,the displacement of ballast particles,the number and the failure rate of bonds are de⁃creased with the model accuracy decreasing,and the contact force between the ballast particles is generally de⁃creased with the model accuracy decreasing.However.the contact forces and the distribution of force chains become more uniform with the improvement of model accuracy.