首页|膨胀土地基膨胀特性对无砟轨道路基变形性能的影响

膨胀土地基膨胀特性对无砟轨道路基变形性能的影响

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  • 国家科技期刊平台
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为研究膨胀土地基浸水膨胀行为对无砟轨道路基力学与变形特征的影响，首先，基于温度场等效湿度场理论，引入材料热属性，通过热-力耦合分析方法模拟膨胀土的膨胀特性;其次，建立双线铁路无砟轨道-基床-膨胀土地基的三维数值模型，并验证其可靠性;最后，研究膨胀土地基的膨胀潜势(以热膨胀系数表征)和膨胀区域(以膨胀区域纵向长度表征)对无砟轨道路基力学与变形性能的影响。研究结果表明:在局部浸水情况下，膨胀土地基的膨胀行为引发了无砟轨道结构的隆起、纵向不平顺和侧向倾斜现象;这些现象随着膨胀土地基的膨胀潜势增大和膨胀区域扩大而更加明显;当膨胀土地基中的膨胀区域沿路基纵向长度超过10 m后，无砟轨道结构的侧倾角度增幅很小;基床层填料的压缩引起路基隆起变形衰减，其衰减率随地基膨胀潜势增大而增大，随地基膨胀区域扩大而减小。本文提出将无砟轨道结构的隆起量、隆起纵向不平顺性以及侧倾角度同时作为膨胀土地区无砟轨道路基的性能控制指标;建议采取降低路基隆起变形横向分布不均匀性和膨胀土地基湿度分布梯度的措施，以减小无砟轨道结构的侧倾程度。
Influence of swelling behavior of expansive soil foundation on deformation performance of ballastless track subgrade
To study the impact of the swelling behavior in expansive soil foundations on the mechanical and deformation characteristics of ballastless track subgrades,firstly,the thermal properties of materials were introduced to simulate the swelling behavior of expansive soils through thermal-force coupling analysis,based on the theory of equivalence between temperature and moisture fields.Secondly,a three-dimensional numerical model of ballastless track-subgrade-expansive soil foundation for double-line railways was established and verified.Finally,the effects of the swelling potential(denoted by the coefficient of thermal expansion)and the swelling area(denoted by the longitudinal length of the swelling area)of the expansive soil foundation on the mechanical and deformation behavior of the ballastless track subgrade were investigated.The results show that localized water immersion causes swelling in the expansive soil foundation,resulting in heave,longitudinal irregularity and lateral tilting of the ballastless track structure.These effects are more pronounced with the increase of swelling potential and area in the foundation.However,when the length of the swelling area along the longitudinal direction of the subgrade exceeds 10 m,there is only a small increase in the lateral inclination angle for the ballastless track structure.Furthermore,the compression of the subgrade fillers results in an attenuation of the heave,and the attenuation rate of the heave increases with the increase of the swelling potential and decreases with the increase of the swelling area in the foundation.The heave amount,longitudinal unevenness of heave and lateral inclination angle of the ballastless track structure are suggested as the performance control indexes for ballastless track subgrades in expansive soils.Additionally,measures should be implemented to mitigate the uneven transverse distribution of subgrade heave and moisture gradient in expansive soil foundations,aiming to alleviate the lateral inclination of the ballastless track structures.

expansive soil foundationheave deformationswelling potentialballastless tracklateral tilting

段君义、曹鹏远、粟雨、林宇亮、杨果林

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南昌大学工程建设学院,江西南昌,330031

中南大学土木工程学院,湖南长沙,410075

高速铁路建造技术国家工程研究中心,湖南长沙,410075

膨胀土地基 隆起变形 膨胀潜势 无砟轨道 侧向倾斜

国家自然科学基金资助项目国家自然科学基金资助项目江西省自然科学基金资助项目江西省自然科学基金资助项目江西省自然科学基金资助项目江西省自然科学基金资助项目中国博士后基金资助项目

522083485220834720232ACG0100320232BAB20408320224BAB21406420224BAB2140632023M731436

2024

10.11817/j.issn.1672-7207.2024.09.025

中南大学学报(自然科学版)
中南大学

中南大学学报(自然科学版)

CSTPCD北大核心
影响因子：0.938
ISSN：1672-7207
年,卷(期)：2024.55(9)