铁道科学与工程学报2025，Vol.22Issue(2)：625-635,11.DOI:10.19713/j.cnki.43-1423/u.T20240554
分级变围压条件下粉土路基填料回弹模量试验研究
Experimental study on resilient modulus of silty subgrade soil with stepped variations of confining pressure
摘要
Abstract
The innovative prestressed subgrade technique enhances soil confinement through horizontal prestress application,achieving dual objectives of subgrade reinforcement and distress mitigation.To investigate the resilient characteristics of silt-based subgrade fillers under horizontal prestress effects,a series of cyclic dynamic triaxial tests were systematically conducted with stepwise confining pressure variations.This experimental program analyzed the evolution patterns of resilient modulus under such boundary conditions and subsequently established an empirical predictive model.The test results indicate that,progressive confining pressure elevation not only increased the resilient modulus of the subgrade soil,but also improve the stress state of samples,so that the specimens exhibiting plastic failure under constant confinement successfully transitioned to elastic stability states.Considerable instantaneous increase of the resilient modulus was observed after each graded increase of the confining pressure,and the resilient modulus gradually stabilized with the increase of vibration cycles of dynamic loads.The vibration cycle interval of stepped varying confining pressure would affect the stable resilient modulus of specimens,and the smaller the vibration cycle interval,the larger the stable value of the resilient modulus was obtained.Regarding the stable samples,the increase of resilient modulus caused by increasing confining pressure with a lower dynamic stress level was larger than that with a higher dynamic stress level.The contributions of stepped increasing confining pressure on improving the resilient modulus may not offset the reduction of the resilient modulus caused by the increase of water content.Based on the experimental results,the existing resilient modulus prediction model was improved,and a developed prediction model incorporates dynamic stress state and stress history of the subgrade soil was established.The resilient modulus of a stable sample under stepped variations of confining pressure was predicted using the developed model,and good prediction results were obtained.The research results can provide scientific basis for further revealing the effect and mechanism of horizontal prestressing reinforcement on subgrade and are of important guiding significance for the design of prestressed subgrade.关键词
粉土路基填料/回弹模量/分阶段变围压/动三轴试验/影响因素Key words
silty subgrade soil/resilient modulus/stepped variation of confining pressure/dynamic triaxial test/influencing factor分类
建筑与水利引用本文复制引用
陈有为,冷伍明,徐方,张期树,董俊利,聂如松,杨奇..分级变围压条件下粉土路基填料回弹模量试验研究[J].铁道科学与工程学报,2025,22(2):625-635,11.基金项目
湖南省自然科学基金青年项目(2023JJ41054) （2023JJ41054）
国家自然科学基金资助项目(51978672) （51978672）
