高速铁路路基粗粒土冻胀机理探析

Frost Heave Mechanism Analysis of Coarse Grained Soil for High Speed Railway Subgrade

针对严寒地区高速铁路路基冻胀的最大变形量应小于5mm的严格要求,就填筑于高速铁路路基的微冻胀填料开展微观研究,以探索其冻胀的内在机制。由于高速铁路路基发生微冻胀时粗骨料和细骨料的相互作用的应力应变关系比较复杂,无法用简单的力学模型来描述细骨料的受力状态,所以应用物理类比法,将二者的相互作用关系利用一个理想的物理模型进行模拟,建立了微冻胀填料不完全填充的冻胀微观力学模型,推导了在细颗粒膨胀过程中细颗粒体积膨胀率与混合物体积变化之间的关系。对其冻胀过程进行了理论分析,得到了微冻胀填料冻胀应力应变路径。该研究成果有利于提高对微冻胀填料冻胀机理的认识。

On account of the strict requirement that the maximum frost heaving deformation of high speed railway subgrade in cold region should be less than 5 mm,research on the micro frost heave filling of high speed railway subgrade is carried out,and frost heave mechanism is explored. The relationship between the stress and strain of coarse aggregate and fine aggregate is very complex when micro frost heave occurs to the high speed railway subgrade,it is impossible to describe the force state of fine aggregate by using simple mechanical model,so physical analogy method is applied. The interaction relationship is simulated by an ideal physical model,a micro mechanical model of imcompletely filled micro frost heave filling was established. The relationship between the volume expansion ratio of imcompletely fine particles and the change of volume mixture is derived during the process of fine particle expansion.The process of frost heaving was analysed in theory,then the stress-strain paths of frost heave of micro frost heave filling was obtained. The results of the study are helpful for developing the frost heave mechanism of micro frost heave filling.