强发育岩溶区桩板路基结构力学性能试验  

Mechanical Performance Test of Pile⁃Slab Subgrade Structure in Strongly Developed Karst Area

作　　者：张磊 ZHANG Lei(China Railway Design Corporation,Tianjin 300308,China)

机构地区：[1]中国铁路设计集团有限公司,天津300308

出　　处：《铁道建筑》2024年第8期111-116,共6页Railway Engineering

基　　金：中国铁路设计集团有限公司科技项目(2023A0253809,2024A0253804)。

摘　　要：强发育岩溶区高速铁路无砟轨道设计施工中,岩溶地层稳定性与路基沉降控制是保障列车运营安全的关键。桩端嵌岩的桩板路基结构是一种适用于岩溶强发育区的路基设计方案,既可解决岩溶顶板附加荷载问题,又能有效消除覆盖土层的压缩沉降。为研究强发育岩溶区无砟轨道桩板路基结构的力学性能,依托高速铁路车站路基开展现场试验,综合分析列车动荷载在路基本体中的传播衰减规律以及桩板结构动静力学承载特征。结果表明:300~350 km/h运行条件下,列车动荷载总体沿45°方向向下传递,主要影响路基面以下5.0 m范围,且在路基基床2.7 m范围内作用效应相对较大;路基本体内列车动荷载实测值小于常规土柱静荷载等效方法计算结果,TB 10001-2016《铁路路基设计规范》方法偏于安全;实测桩板路基板下地基存在一定的地基反力,对承载板受力较为有利;岩溶塌陷风险较小的桩板路基结构设计中,可适当考虑板下地基反力作用,合理控制工程造价。In the design and construction of high speed rail ballastless tracks in strongly developed karst areas,the stability of karst strata and the control of subgrade settlement are key to ensuring the safety of train operation.The low pile plate subgrade structure with embedded rock at the bottom of the pile not only solves the problem of additional load on the karst roof,but also basically eliminates the compression settlement of the covering soil layer.It is a relatively stable subgrade design scheme in areas with strong karst development.In order to study the mechanical properties of ballastless track pile plate structure subgrade in strongly developed karst areas,field tests were conducted based on some high Railway.The distribution pattern of train loads in the basic body of the high speed railway and the mechanical characteristics of the pile plate structure were analyzed.The results show that under the operating conditions of trains with speeds of 300~350 km/h,the train load on the subgrade top was down transmitted almost along the 45°direction,the vertical transmission of train dynamic loads mainly affects the range of 5.0 m below the roadbed surface,and the effect of action is significant within a range of 2.7 m of the roadbed.The calculation adopts standardized methods of TB 10001—2016 Code of Design of Railway Subgrade,the measured values are smaller than the calculated values,which is biased towards safety.The stress on the three layers of steel bars inside the bearing plate is relatively uniform and small due to the reaction force of the bottom soil of the plate on the bearing plate.For sections with lower risk of karst collapse,the calculation of the pile plate structure can appropriately consider the reaction of the soil between the piles,thereby reducing engineering investment.

关 键 词：铁路路基 桩板路基结构 现场试验 强发育岩溶区 无砟轨道 列车动荷载 

分 类 号：U213.14[交通运输工程—道路与铁道工程]