铁道标准设计2026，Vol.70Issue(1)：54-62,9.DOI:10.13238/j.issn.1004-2954.202402270001
川中红层不均匀膨胀特性及对路基上拱影响机制
Non-Uniform Swelling Characteristics of Red Beds in Central Sichuan and Their Mechanism on Subgrade Upheaval
摘要
Abstract
The continuous upheaval deformation of high-speed railway subgrades in the Red Bed area of central Sichuan poses a potential long-term threat to operational safety.Based on an actual engineering project,micro-and meso-scale tests,triaxial swelling tests,and in-situ layered upheaval monitoring of the Red Beds in central Sichuan were carried out.The study analyzed,across multiple scales,the non-uniform swelling characteristics caused by differences in mineral composition,microstructure,and rock-layer structure,and explored their mechanism on the long-term subgrade upheaval.The results showed that the Red Beds in central Sichuan,composed of interbedded mudstone and sandstone,contained multiple sets of horizontal bedding planes.The expansive clay mineral content varied greatly among the rock layers,resulting in high swelling pressures with a wide range of values,where the differential stress could exceed 1.5 MPa.Combined with the preferred orientation of mineral particles in the microstructure,the swelling strain perpendicular to the bedding direction was significantly greater than that parallel to the bedding direction,with an anisotropic swelling coefficient ranging from 0.34 to 0.71.This non-uniform swelling effect was sufficient to generate macro-and micro-cracks and to promote their propagation along the horizontal bedding planes.Analysis of the field monitoring data on Red Bed subgrade upheaval showed that the upheaval developed rapidly during the first 1-2 years of operation,although the rate gradually decreased.After two years of operation,the upheaval rate stabilized at 5-11 mm/a and exhibited periodic fluctuations corresponding to alternating rainy and dry seasons.The primary upheaval stratum did not occur in the shallow surface but was controlled by the distribution of joints and fractures hydraulically connected to the external environment,with the maximum upheaval depth reaching 15 m.Overall,the non-uniform swelling of the Red Beds in central Sichuan tends to generate cracks that propagate along bedding planes and continuously develop under the influence of periodic environmental changes.This process constitutes an important mechanism for the sustained,non-convergent upheaval deformation of the subgrade over many years.关键词
高速铁路/路基/川中红层/不均匀膨胀/分层上拱/节理裂隙Key words
high-speed railway/subgrade/Red Beds in central Sichuan/non-uniform swelling/layered upheaval/joints and fractures分类
交通工程引用本文复制引用
李洋,余飞,陈善雄,黄康,戴张俊..川中红层不均匀膨胀特性及对路基上拱影响机制[J].铁道标准设计,2026,70(1):54-62,9.基金项目
国家自然科学基金项目(42172308) （42172308）
湖北省重点研发计划项目(2022BAA036) （2022BAA036）
