红层改良路基填料力学特性及累积变形预测OA
Mechanical Properties and Cumulative Deformation Prediction of Improved Red-Bed Subgrade Fill Material
[目的]西南地区存在红层路基工程特性差和运输成本高的问题.[方法]采用现场红层黏土开展物理改良,向红层黏土掺入 50％不同粒径混合的泥岩碎石,形成土石混合的优质红层铁路路基填料.通过大型直剪试验和动三轴试验,探究红层改良填料在列车动荷载作用下的力学特性和累积变形规律,建立累积塑性应变预测模型,计算分析铁路路基的累积沉降量.[结果]研究表明:(1)红层土石混合改良填料的静力特性受法向应力和含水率影响,在最优含水率 10.26％下抗剪强度最大,因受湿化作用超过 10.26％试样的抗剪强度骤降;(2)改良填料的累积应变受含水率、围压和动应力影响,轴向累积应变随含水率和动应力的增加而增大,随围压的增加而减小,且含水率的影响程度最大,在最优含水率 10.26％和 50 kPa 围压下,改良填料的临界动应力达到最大值 195 kPa,在工程运用中需严格控制含水率,以保证路基填料的力学强度;(3)综合改良填料的静、动力特性,基于AASHTO 模型建立能反映含水率、围压和动应力影响的红层累积塑性应变预测模型,应用模型预测 10 m 高的铁路红层改良路基,其累积沉降量为 12.92 mm,满足规范要求.[结论]预测模型可为红层地区的铁路路基设计、施工及运营提供依据.
[Objective]There are problems with the poor engineering properties of red-bed subgrades and high transportation costs in southwestern China.[Methods]Locally sourced red-bed clay was physically improved by incorporating 50％mudstone gravel with mixed particle sizes to produce a high-quality soil-stone mixture for use as red-bed railway subgrade fill.Through large-scale direct shear tests and dynamic triaxial tests,the mechanical properties and cumulative deformation patterns of the improved red-bed fill material under dynamic train loading were explored,and a cumulative plastic strain prediction model was established to calculate and analyze the cumulative settlement of the railway subgrade.[Results]The results showed that:(1)the static mechanical properties of the improved red-bed soil-stone mixture were affected by normal stress and moisture content,with the maximum shear strength occurring at the optimum moisture content of 10.26％.Due to the wetting effect,the shear strength of samples with a moisture content exceeding 10.26％decreased sharply.(2)The cumulative strain of the improved fill material was affected by moisture content,confining pressure,and dynamic stress.The axial cumulative strain increased with increasing moisture content and dynamic stress and decreased with increasing confining pressure,with moisture content having the greatest influence.At the optimum moisture content of 10.26％and a confining pressure of 50 kPa,the critical dynamic stress of the improved fill material reached a maximum of 195 kPa.It was necessary to strictly control the moisture content in engineering applications to ensure the mechanical strength of the subgrade fill material.(3)Considering the static and dynamic properties of the improved fill material,a cumulative plastic strain prediction model for the improved red-bed fill material that accounted for the effects of moisture content,confining pressure,and dynamic stress was established based on the AASHTO model.The model predicted a cumulative settlement of 12.92 mm for a 10 m-high improved red-bed railway subgrade,which met the relevant specification requirements.[Conclusion]The prediction model can provide a basis for the design,construction,and operation of railway subgrades in red-bed regions.
刘语诗;徐华;王栋;张杰
成都理工大学环境与土木工程学院,成都 610059成都理工大学环境与土木工程学院,成都 610059||西南交通大学土木工程学院,成都 610031中铁二院工程集团有限责任公司,成都 610031西南交通大学土木工程学院,成都 610031
交通工程
铁路路基红层填料动力特性临界动应力累积应变预测
railway subgradered-bed fill materialdynamic propertiescritical dynamic stresscumulative strain prediction
《铁道标准设计》 2026 (8)
33-42,10
国家重点研发计划项目(2016YFB1200401-102D)
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