建筑垃圾掺量和碾压方式对改良粉土路基变形特性的影响OA

To address the engineering challenges of difficult compaction and molding of Yellow River alluvial silt and the difficulty in guaranteeing subgrade filling quality,a technical solution utilizing urban waste construction waste for the physical improvement of silt subgrade is proposed.Through laboratory geotechnical tests,the influence of construction waste contents on the physico-mechanical properties of Yellow River alluvial silt is investigated,and the mechanism of construction waste improving silt subgrade is revealed.On this basis,relying on the subgrade engineering of the newly built Xi'an-Ankang High Speed Railway,a three-dimensional dynamic finite element model integrating an equivalent moving load subroutine is constructed.Combined with on-site monitoring data,the deformation evolution laws and compaction mechanism of the improved subgrade under dynamic loading are analyzed.The results indicate that incorporating rough-surfaced construction waste particles can effectively reshape the internal structure of the silt,form a load-bearing skeleton,and significantly enhance its internal friction angle and resistance to compressive deformation.Comprehensively considering subgrade performance and construction efficiency,the optimal compaction process is determined to be a 20%construction waste content(mainly crushed concrete),a 40 cm loose paving thickness,supplemented by a"low speed and multiple strong vibrations"combination.The deep impact effect generated by large amplitude overcomes the frictional resistance between coarse aggregates,thereby ensuring the overall compaction quality of the subgrade.The research results can provide a technical reference for compaction issues of special soil subgrades.