煤粉脏污侵入下加筋道砟界面劣化机理及变形特性研究

During the operation process, the infiltration and accumulation of external fines are inevitable due to the discrete nature of geogrid stabilized ballast system. However, it has been widely acknowledged that the service performance of geogrid stabilized ballast decreases with the presence of fouling particles. In reaction to this phenomenon, the laboratory test, numerical analysis and theoretical analysis will be employed to systematically study the deterioration behavior of geogrid stabilized ballast with special considerations of the progressive accumulation of coal fouling, the magnitude and the amplitude of the actual cyclic loading. The synergism mechanism of interacting components (i.e., geogrid, ballast and coal fines ) and the distinctions in particle contact and load transfer behavior under various levels of fouling will be revealed. Simultaneously, the content of coal fouling will serve as an alternative index to quantitatively assess the extent of interface deterioration, and the mesoscopic factor that intrinsically govern the development of interface strength will be recognized. Meanwhile, the design parameters will be optimized based on deformation performance, and a regression equation that predict the long-term settlement will be proposed. Under the guidance of the regression equation, reasonable maintenance opportunity will be determined. The results obtained from this project will perfect the design criteria for geogrid stabilized ballast and promote its application, thus, holding great significance in research and engineering practice.

加筋道床散体结构本质决定了运营过程中外源脏污颗粒的附着、侵入不可避免。针对脏污颗粒侵入时道床服役性能下降的客观现象，本项目以煤粉颗粒为脏污源，充分考虑煤粉颗粒渐进侵入过程和列车荷载特征，采用室内模型试验、离散元数值模拟及理论分析相结合的手段对煤粉颗粒侵入下加筋道床服役性能劣化行为进行系统研究，揭示筋材-煤粉-道砟颗粒三者间协同作用机制，理清煤粉脏污侵入与颗粒接触和力的传递模式间互联规律，形成以煤粉含量为替代指标的界面劣化识别方法并明确界面强度劣化的细观主控因素。同时，以沉降控制为目的，优化加筋道床主要设计参数，提出考虑脏污侵入的长期沉降预测方法，据此确定适宜的维护时机。本项目研究成果可完善加筋道床设计准则，指导其在工程中应用与推广，具有重要的学术价值和工程意义。

加筋道床散体结构本质决定了运营过程中外源脏污颗粒的附着、侵入不可避免。针对脏污颗粒侵入时道床服役性能下降的客观现象，本项目以煤粉颗粒为脏污源，充分考虑煤粉颗粒渐进侵入过程，对煤粉颗粒侵入下加筋道床服役性能劣化行为以及格栅-道砟相互作用影响进行系统研究，明确了加筋道床服役性能劣化的细观主控因素。同时，以界面强度为优化目标，科学构建加筋效果评价体系，系统探讨了格栅几何结构、填料颗粒定向、网孔尺寸等因素对加筋行为的影响机制。研究成果获得山西省科技进步一等奖1项和中国土工合成材料与工程协会科技进步二等奖各1项，可为重载铁路加筋道床服役性能持续提升提供参考。