新型桩板结构路基在季节冻土区的适用性  

Applicability of Novel Pile-Plank Embankment in Seasonally Frozen Regions

作　　者：张树明[1] 蒋关鲁[1] 杜登峰 廖祎来 薛元[2] 李安洪[2] ZHANG Shuming;JIANG Guanlu;DU Dengfeng;LIAO Yilai;XUE Yuan;LI Anhong(School of Civil Engineering,Southwest Jiaotong University,Chengdu 610031,China;China Railway Eryuan Engineering Group Co.,Ltd.,Chengdu 610031,China)

机构地区：[1]西南交通大学土木工程学院,四川成都610031 [2]中国中铁二院工程集团有限责任公司,四川成都610031

出　　处：《西南交通大学学报》2021年第3期541-549,共9页Journal of Southwest Jiaotong University

基　　金：国家自然科学基金(51878577);中国铁路总公司重大课题(2016G002-A)。

摘　　要：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.In order to control the frost heaving damage in the seasonally frozen regions of the Moscow-Kazan high-speed railway, a novel pile-plank subgrades with an insulation board was proposed. Comparing the performance of three kinds of thermal insulation materials, expanded polystyrene(EPS) foam board, polyurethane(PU) board and extruded polystyrene(XPS) foam board shows that the XPS insulation board could be used in the new subgrade for its better performance in heat insulation, waterproof, impervious and compressive properties.The thermo-elasto-plastic model was established to study the influences of laying range, insulation board thickness,filling height, and external temperature on the mechanical deformation of the new type subgrade. The results show that when the laying range of the insulation board is extended to the signal wire slot, it can do better to preventing the downward transfer of negative temperatures(reducing the frozen depth), and diminishing the harmful effect of soil frost heaving surrounding the pile-plank structure. With increasing board thickness, the heaving amount decreases exponentially and frozen depth decreases close to a parabolic curve. The upper surface of the insulation board can prevent the downward transfer of negative temperatures and its lower surface plays a role in controlling the soil temperature dissipating under embankment. Increasing the filling height of embankment is helpful to suppress the subgrade heaving amount and reduce the usage thickness of the insulation board. The insulation board thickness should be greater than 0.4 m when the filling height is 0.8 m;and the board thickness should be greater than 0.31 m when the filling height is 2.8 m.

关 键 词：新型桩板结构 XPS保温板 季节性冻土区 数值仿真 高速铁路 

分 类 号：TU47[建筑科学—结构工程]