无砟轨道聚氨酯碎石防排水型基床动力响应研究

提出了一种适用多雨地区聚氨酯碎石防排水型基床结构，并对结构的渗透系数以及力学特性开展试验，最后建立有限元模型对普通基床和聚氨酯碎石强化基床的动力响应特性进行深入分析，得出以下结论:渗透系数随着聚氨酯的掺量逐渐减少，聚氨酯掺量8.00 %时，渗透系数小于10?4 cm/s，满足高速铁路防渗要求；80 ℃高温下聚氨酯抗压强度、回弹模量分别衰减58.02 %，41.70 %，浸水以及自然状态下衰减较小；铺设聚氨酯碎石后动响应与普通基床结构类似，但聚氨酯碎石具有良好的减振特性，能够进一步减弱基床的振动响应；为减少铺设聚氨酯碎石强化层后基床建造的经济成本，聚氨酯碎石的经济合理厚度宜控制在5～8 cm范围内。

Study on Dynamic Response of Waterproof and Drainage Type Polyurethane Gravel Bed of Ballastless Track

A kind of applicable polyurethane gravel bed is proposed. The tests were carried out to analyze the permeability coefficient and mechanical properties of the structure, then a finite element model was established to study the dynamic response characteristics of normal bed and the bed reinforced by polyurethane gravel. The conclusions are as follows, the permeability coefficient decreases with the content of polyurethane, and is less than 10-4cm/s at 8% of polyurethane, meeting the anti-seepage requirement of high-speed railway; at 80°C, the compressive strength and rebound modulus of polyurethane are attenuated by 58.02. % and 41.70% respectively, and has less attenuation in soaking and natural state; after polyurethane gravel is applied, the dynamic response is similar to that of normal bed, however, polyurethane gravel bed performs well in vibration attenuation and may further weaken the vibration response of the bed; for the purpose of reducing the construction cost, the reasonable thickness of the polyurethane gravel layer should be controlled within the range of 5~8cm.