无砟轨道地基泥岩膨胀变形及水分迁移速率衰减规律

高铁无砟轨道对膨胀变形值要求极为严格，地基膨胀泥岩浸水引起的胀缩变形将对行车安全性和舒适性产生影响。为研究泥岩随浸水位置水平距离和深度增加时膨胀速率及水分迁移速率的衰减规律，以兰新铁路第二双线某处典型膨胀泥岩为研究对象，通过顶部和侧面两种浸水方式进行三组重塑泥岩膨胀变形试验。试验结果表明:距离浸水管水平长度不同，膨胀时程曲线变化规律不同。距离浸水管水平长度越远，膨胀速率越慢，水分迁移速率亦越小；侧面浸水时沿深度方向首先引起底部土体膨胀。通过对试验数据进一步分析，提出用初期平均渗透系数分析水分迁移速率衰减规律，经计算可知，水分迁移速率随与浸水管水平距离和垂直距离的增大均呈衰减趋势。研究结果可为地基泥岩上拱病害治理及预警提供理论支撑。

Attenuation law of expansion deformation rate and water migration rate on mudstone of ballastless track foundation

Ballastless track of high-speed rail has a very strict requirement for expansion deformation value, for the expansion-shrinkage deformation caused by flooding of foundation expansion mudstone will threaten the driving security and comfort. To study the attenuation law of expansion rate and moisture migration rate of mudstone with the increase of horizontal distance and depth of flooding position, a typical expensive mudstone of the second double track of Lanzhou-Xinjiang Railway is taken as the object of study, and three groups of remolding mudstone deformation testing on the top and side are conducted with two methods of flooding. The test results show that as the horizontal length to flooding pipe is different, the expansion-travel curve has different change rules: the further the horizontal length to flooding pipe is, the slower the expansion rate is, and the smaller the moisture migration rate is; during the lateral flooding, the expansion of bottom soil mass will be caused firstly along the direction of depth. Through further analysis on the test data, it is proposed to analyze the attenuation law of moisture migration rate with initial average permeability coefficient, and it is known through calculation that the moisture migration rate shows a tendency of attenuation with the increase of distance to flooding pipe and also with the increase of depth. The research results can provide a theoretical support for control and early warning of foundation mudstone arching-up.