基于离心模型试验的路堤地基差异沉降传递规律及控制限值研究

Study onTransfer Behavior and Control Limit Value of Differential Settlements of Embankment Foundation Based on Centrifugal Model Tests

为研究地基差异沉降在路堤中的传递扩散特性及对路基面不均匀变形的影响规律,构建了错台式和渐变式2种地基差异沉降模型,研制了一套能够在离心机运转过程中实现地基差异沉降的实时精确控制装置,设计6组离心模型试验,分析路堤高度、地基差异沉降渐变段长度等因素对路基面不均匀变形的影响,提出了基于路基面折角限值的地基差异沉降控制标准。试验研究表明:(1)地基差异沉降引起的路基面不均匀变形沿线路纵向均呈S型分布特征;(2)高路堤和长渐变段均会降低地基差异沉降对路基面不均匀变形的影响程度;(3)提出的满足线路平顺性要求的路堤地基差异沉降允许值,对完善铁路路基沉降变形控制的参数指标有指导意义。

Staggered platform and gradually changed models of differential settlements of embankment founda- tion were built so as to master the law of differential settlement transfer in the subgrade and its mechanism of influence on the uneven deformations of subgrade surface A set of control devices was developed, which can a- chieve accurate real-time control of differential settlements of embankment foundations under centrifugal load- ing conditions. By using this set of devices, six groups of centrifugal model tests were designed to analyze the influence of embankment height and lengths of transition sections of differential foundation settlements etc on uneven deformations of subgrade surface. The standards for control of differential settlements was set on the basis of limited values of the folded angle of subgrade surface. The tests show as follows： 1） Uneven deforma- tions of subgrade surface caused by differential settlements are distributed longitudinally along the line in the shape of S; 2） both high embankments and long transition sections can lessen the impact of differential settle- ments on uneven deformations of subgrade surface; 3）presentation of the allowable values of differential settle- ments of embankment foundation meeting the requirements for line smoothness plays a positive role in impro- ving the indexes of parameters for control of railway subgrade settlement deformations.