中文摘要：

针对双块式无砟轨道和路基的结构特点，建立车辆-轨道-路基垂向耦合动力学频域分析模型，模型充分考虑机车车辆、双块式无砟轨道和路基的相互耦合作用。车体、转向架和轮对被视为多刚体系统，一系和二系悬挂用弹簧阻尼元件模拟；双块式无砟轨道和路基系统视为多层叠合梁模型，彼此用弹簧阻尼元件联结。推导双块式无砟轨道和路基系统振动响应的解析表达式，计算得出轨道和路基耦合系统的动柔度特性，结合虚拟激励法提出该模型在轨道随机不平顺激励时动力学响应的求解方法，分析高速列车荷载作用下双块式无砟轨道和路基的随机振动响应及其振动传递特性。研究结果表明：在10～5000 Hz频率范围内，钢轨的动柔度幅值远大于道床与路基的动柔度幅值，而道床动柔度幅值在30 H z以上频段大于路基的动柔度幅值；钢轨振动的能量分布频段较道床和路基要宽，道床和路基振动主要集中于163．9 Hz左右频段；对于无砟轨道和路基耦合系统的振动功率，钢轨最大，道床次之，路基最小；道床和路基振动功率在100 Hz 以上中高频段，衰减比较快，而在100 Hz以下低频段，其衰减不明显；在300 Hz以上高频段，钢轨-路基间振动衰减较大，其主要原因是受钢轨-道床间振动衰减波动的影响。

英文摘要：

In combination with double-block ballastless track and subgrade structure characteristics ,a vehicle-track-subgrade vertical coupled dynamic model was established in the frequency domain .In this model ,the en-tire vehicle was represented by a rigid body model consisting of one car body ,two bogies and four wheelsets connected to one another with springs and dampers ;the double-block ballastless track and subgrade systems were considered as a multilayer beam model connected to each other with springs and dampers .The analytic ex-pressions of vibration responses were derived ,and the admittances of the coupled ballastless track and subgrade system were calculated .Combined with the virtual excitation method ,the solution of random dynamic respon-ses under excitation of random track irregularities was put forward .The random vibration responses and trans-fer characteristics of the double-block ballastless track and subgrade system under loading of running high-speed trains were analyzed .The results show as follows ：Within the range of 10~5000 Hz ,the magnitudes of the rail displacement admittances are much higher than those of the track slab and subgrade displacement admit-tances ,and in the frequency bands above 30 Hz ,the magnitudes of the displacement admittances of track slab are larger than those of the displacement admittances of subgrade ;the frequency bands with rail vibration ener-gy distributed are wider than those with track slab and subgrade vibration energy distributed ,vibrations of track slab and subgrade are mainly concentrated in the frequency bands of about 163 .9 Hz ;out of the vibration power of the coupled ballastless track and subgrade system ,the rail lies the first ,the track slab the second and the subgrade the minimum ;in the middle and high frequency bands above 100 Hz ,the vibration power of track slab and subgrade attenuates fast whereas in the low frequency bands below 100 Hz their vibration attenuation is not obvious ;in the high frequency bands above 300 Hz ,strong vibration atten