无砟轨道层间动水压力试验设计

无砟轨道层间界面是其薄弱环节，雨水侵入会加剧层间损伤.为研究无砟轨道层间离缝内动水压力分布规律，建立无砟轨道层间脱空平面计算模型，分析脱空深度与开口量对脱空区域垂向位移的影响，确定与现场实测接近的脱空深度；并设计无砟轨道层间脱空模拟装置，验证高频荷载作用下该装置的有效性；基于此装置，开展层间离缝动水压力试验，研究荷载频率、离缝开口量对动水压力的影响.结果表明：当荷载频率为25 Hz，幅值为1.1 kN时，层间脱空模拟装置板端最大垂向相对位移与现场测试结果吻合，表明该装置能模拟层间动水；在高频荷载作用下，层间离缝内水压力正负交替变化，动水压力沿离缝深度方向增大，在离缝尖端水压力最大为15.794 kPa；荷载频率从15 Hz提高至25 Hz时，最大动水压力从1.646 kPa增长到15.794 kPa，约增大10倍；开口量从8 mm增加至14 mm时，最大动水压力从8.320 kPa增大到15.794 kPa，约增大2倍.

Experimental Design of Hydrodynamic Pressure in Ballastless Track Crack

The interlayer is the weak link of the ballastless track and the rainwater intrusion can aggravate the debonding damage. To study the distribution of hydrodynamic pressure in the interlayer crack of ballastless track under the high-speed train load, a planar calculational model is established, the effects of debonding depth and crack opening on the vertical displacement are analyzed, and a debonding depth close to that measured in the spot is determined. A ballastless track crack simulation device is designed to verify the effectiveness of the device under high frequency loading; based on this device, hydrodynamic pressure experiments on the interlayer debonding are carried out to investigate the effects of load frequency and crack opening on the hydrodynamic pressure. The results show that when the load frequency is 25 Hz and the amplitude is 1.1 kN, the maximum vertical relative displacement at the plate end of the simulation device is the same as the spot test results, indicating that the device can be used for interlayer hydrodynamic simulation; under the high frequency load, the water pressure in the interlayer debonding alternately changes positively and negatively, and the hydrodynamic pressure increases along the depth direction of the crack, with the maximum water pressure at the tip of the crack being 15.794 kPa. When the load frequency increases from 15 Hz to 25 Hz, the maximum hydrodynamic pressure increases from 1.646 kPa to 15.794 kPa, which is about 10 times greater. When the opening is increased from 8 mm to 14 mm, the maximum hydrodynamic pressure increases from 8.320 kPa to 15.794 kPa, which is about 2 times greater.