道面结构不均匀冻胀模型试验及数值模拟

Model test and numerical simulation of uneven frost heave of pavement structure

摘要:

为更好地揭示道面结构内部温度场、水分场和冻胀量的基本规律，为防治道面结构不均匀冻胀病害提供有效的理论依据，自主设计了道面结构不均匀冻胀模型试验箱，开展了外部水分入渗道肩和道面结构不均匀冻胀模型试验，基于ABAQUS的二次开发实现了道面结构内部水热力三场耦合数值模拟，并将数值模拟结果与模型试验结果进行了对比分析.结果表明：模型试验直观地模拟了跑道与道肩冻胀错台现象，并阐明了错台的原因是跑道与道肩的不均匀冻胀；客观地揭示了道面结构内部温度场、水分场及冻胀量的发展规律；水分通过道肩渗入道面结构引发水分场的重分布；道面结构不均匀冻胀是水热耦合作用的产物，温度梯度和降温速率影响着冻结过程中水分的迁移和积聚，水分场的重分布反过来也影响着温度的传递.数值模拟结果与模型试验结果吻合良好，且符合实际，数值模型的正确性和适用性得到了验证.结合模型试验的客观性优势和数值模拟的全面性优势有助于深入研究更多寒区构筑物地基的不均匀冻胀病害问题.

Abstract:

The paper is intended to reveal the basic laws of temperature field, water field and amount of frost heave inside the pavement structure, and to provide the theoretical basis for the prevention and cure of uneven frost heave. The test chamber of uneven frost heave of pavement structure was originally designed. The model tests of external water infiltration and uneven frost heave of pavement structure were conducted. The numerical simulation of the three-stage coupling of hydro-thermal-stress was realized on the basis of the targeted secondary exploitation of ABAQUS. The comparison of numerical simulation results and model test results were discussed from three aspects, i.e. temperature field, water field and amount of frost heave. The results showed that: the model test intuitively simulated the phenomenon of faulting of slab ends between runway and the shoulder. It illustrated that the cause of faulting of slab ends is the uneven frost heave of the runway and the shoulder. The basic development laws of uneven frost heave of pavement structure were revealed objectively. The external water infiltration has a great impact on water field redistribution. Uneven frost heave of pavement structure is the result of the coupling of temperature field and water field inside pavement structure. The cooling rate and temperature gradient impact on the water migration and accumulation, and in turn, the water field redistribution affects the delivery of temperature. The numerical simulation results were in good agreement with the model test results, both of which were consistent with the actual. The correctness and applicability of the numerical model were verified. The combination of the objective advantages of model test and the comprehensive advantage of numerical simulation contributes to in-depth research on the uneven frost heave of other structures in cold region.