铁路基床翻浆冒泥病害成因的细观机理分析

基于朔黄铁路基床填料动力响应特性试验数据,建立PFC2D饱和粗颗粒土动三轴数值模型,选用线性黏结颗粒接触反映粗颗粒土的黏结特性,从细观力学和几何学角度研究翻浆冒泥病害形成的细观机理。结果表明:该数值模型能较好地反映粗颗粒土的动力响应特性。振动荷载通过改变土体颗粒与颗粒之间的接触荷载,破坏颗粒间的黏结键,形成自由颗粒和孔隙,造成基床软化,并最终形成翻浆冒泥病害。围压和土体颗粒间黏结作用越小,试样越容易发生软化,形成翻浆冒泥病害,基床强化应从改善基床表层和道床的围压状态以及提高颗粒间的黏结强度两方面采取措施。

Meso-mechanism Analysis of The Cause of Mud-flushing Disease in Railway Subgrade

Based on experimental data of dynamic response characteristics of foundation bed packing for Shuohuang Railway, a PFC2D saturated coarse-grained soil dynamic triaxial numerical model was established, and linear cement particle contact was selected to reflect the cohesive characteristics of the coarse-grained soil and the mud blowing was studied from the perspective of micromechanics and geometry. Mesoscopic mechanism of disease formation. The results show that the numerical model can better reflect the dynamic response characteristics of coarse-grained soil. Vibration load changes the contact load between the soil particles and the particles, destroys the bonding bonds between the particles, forms free particles and pores, causes the softening of the foundation bed, and finally forms the mud and mud disease. The smaller the confining pressure and the bonding between the soil particles, the easier the sample will soften and the formation of mud-flushing disease. The strengthening of the foundation bed should be taken from two aspects: improving the confining pressure state of the surface of the foundation bed and the track bed and increasing the bonding strength between particles.