摘要
粗粒土被广泛用作铁路路基填料,其蠕变特性对路基的长期沉降与服役性能有重要影响。利用自制粗粒土填料单元模型试验系统,开展系列二维蠕变试验,探索竖向应力、降雨入渗等因素对蠕变及颗粒破碎的影响;试验后对试样进行颗粒分析,据此建立能同时考虑降雨入渗量、破碎率Bg和荷载的双曲线蠕变预测模型,并且基于确定的静力荷载分布模式及含水率分布公式,建立了粗粒土路基蠕变变形分析模型,分析不同轨道型式条件的路基蠕变变形。结果表明,在50~300 kPa荷载作用下,粗粒土填料蠕变稳定后应变为0.05%~0.101%,且呈衰减型增长趋势;在蠕变过程中颗粒破碎以大粒径颗粒破裂为主、研磨为辅,降雨入渗导致粗粒土填料的颗粒破碎,粒径发生改变;粒组含量的变化总量随荷载增大而显著增大,随降雨入渗强度增加呈先迅速增加而后缓慢增加的趋势;蠕变预测模型计算值与试验值较为吻合,降雨入渗引起路基蠕变变形增幅可以达到80%。研究结果可为高速铁路粗粒土路基变形分析提供参考。
Coarse-grained soil is widely used as railway subgrade filler,and its creep characteristics have great influence on the long-term settlement and service performance of subgrade.A series of two-dimensional creep tests are carried out by using the self-made coarse-grained soil filler unit model test system to explore the effects of vertical stress,rainfall infiltration and other factors on creep and particle breakage.After the test,the particle analysis of the sample is carried out,based on which a hyperbolic creep prediction model is established,which could simultaneously consider rainfall infiltration,breakage index Bg and load.Based on the determined static load distribution model and water content distribution formula,the creep deformation analysis model of coarse-grained soil subgrade is established,and the creep deformation of subgrade under different track types is analyzed.The results show that under the load of 50 kPa to 300 kPa,the strain of coarse-grained soil filler after creep stability is 0.05%to 0.101%,showing an increasing trend of attenuation.In the creep process,the particle breakage is mainly caused by large particle breakage,supplemented by grinding,and the particle breakage size of coarse-grained soil filler changes due to rainfall infiltration.The total change of particle content increases significantly with the increase of load,and then increases rapidly with the increase of rainfall infiltration intensity.The calculated values of creep prediction model are in good agreement with the experimental values,and the increase of subgrade creep deformation caused by rainfall infiltration can reach 80%.The research results can provide reference for deformation analysis of coarse grained soil subgrade of high-speed railway.
作者
王启云
康健
张丙强
魏心星
肖南雄
项玉龙
WANG Qiyun;KANG Jian;ZHANG Bingqiang;WEI Xinxing;XIAO Nanxiong;XIANG Yulong(College of Civil Engineering,Fujian University of Technology,Fuzhou 350118,China;College of Civil and Construction Engineering,Hunan Institute of Technology,Hengyang 421002,China)
出处
《铁道标准设计》
北大核心
2024年第7期70-77,共8页
Railway Standard Design
基金
福建省自然科学基金项目(2020J01884)
湖南省教育厅科学研究项目优秀青年项目(21B0803)
湖南工学院科研启动基金项目(HQ21029)。
关键词
铁路路基
粗粒土
蠕变
颗粒破碎
模型试验
降雨入渗
railway subgrade
coarse grained soil
creep
particle breakage
model test
rainfall infil-tration
