To simulate the fatigue characteristics of the pile-board structure under long-term dynamic load, using the in-situ dynamic testing system DTS-1, the forced vibration loading was repeated one million times at differen...To simulate the fatigue characteristics of the pile-board structure under long-term dynamic load, using the in-situ dynamic testing system DTS-1, the forced vibration loading was repeated one million times at different cross-sections of the pile-board structure for high-speed railway. The dynamic deformation, permanent deformation and dynamic stress of main reinforcements were measured. The test results show that the dynamic responses of the pile-board structure almost did not vary with the forced vibration times under the simulated trainload. After one million times of forced vibration, the permanent deformations of the midspan section of intermediate span and midspan section of side span were 0.7 mm and 0. 6 mm, respectively, and there was no accumulative plastic deformation at the bearing section of intermediate span.展开更多
基金Key Subject for Science Research and De-velopment Plan of Railway Ministry (No.2006G004-B)
文摘To simulate the fatigue characteristics of the pile-board structure under long-term dynamic load, using the in-situ dynamic testing system DTS-1, the forced vibration loading was repeated one million times at different cross-sections of the pile-board structure for high-speed railway. The dynamic deformation, permanent deformation and dynamic stress of main reinforcements were measured. The test results show that the dynamic responses of the pile-board structure almost did not vary with the forced vibration times under the simulated trainload. After one million times of forced vibration, the permanent deformations of the midspan section of intermediate span and midspan section of side span were 0.7 mm and 0. 6 mm, respectively, and there was no accumulative plastic deformation at the bearing section of intermediate span.
文摘针对莫喀(莫斯科—喀山)高速铁路季节性冻土区路基冻胀病害防治问题,提出了铺设保温板垫层的新型桩板结构路基.通过对聚苯乙烯泡沫塑料板(EPS)、聚氨酯板(PU)和挤塑聚苯乙烯泡沫塑料板(XPS)3种保温材料性能的对比分析,发现新型桩板结构路基中的保温板可采用在保温隔热、隔水防渗和抗压性能方面表现良好的XPS保温板.通过建立热弹塑性冻胀计算模型,研究了冻胀力作用下保温板铺设范围、厚度、路基填高和外界温度对新型桩板结构路基受力变形的影响.结果表明:当保温板铺设范围延伸到线路两端的信号线槽处时,可以更好地阻滞外界负温向下传递(减小冻深),抑制因桩板结构周边土体冻胀对结构物产生的不良影响;随着保温板厚度的增大,冻胀量呈指数形式减小,冻深呈抛物线形减小,保温板上表面处起到抑制外界负温向下传递的作用,下表面处起到控制下部土体温度耗散的作用;增大路基填高,有利于抑制路基冻胀量,减少保温板的使用厚度,当路基填高0.8 m时,保温板垫层厚度需大于0.40 m;当路基填高2.8 m时,保温板垫层厚度需大于0.31 m.
