{"title":"Study on the impact of rock shape and volume fraction on the dynamic properties of soil-rock mixtures","authors":"Libing Du , Xinrong Liu , Zhiyun Deng","doi":"10.1016/j.trgeo.2025.101539","DOIUrl":null,"url":null,"abstract":"<div><div>The microstructure of a soil–rock matrix (SRM) is a determinant of its macroscopic physical and mechanical attributes. The influence of the shape and volume fraction (VF) of rock blocks on the dynamic properties of the SRM has not been subjected to quantitative analysis. Consequently, a suitable construction technique was developed for the fabrication of small-scale triaxial specimens incorporating artificial rocks of various shapes. A series of homogeneous SRM specimens with differing rock VFs and shapes were fabricated. These specimens were then exposed to a long-term dynamic load consisting of 15,000 cycles at a frequency of 1 Hz. The principal findings are summarized as follows: The construction method proposed is capable of producing small artificial rocks with dimensions of 3 mm or 5 mm in arbitrary shapes while maintaining consistency with the prototypes. The method holds significant promise for application in geotechnical testing. Under long-term dynamic loading, the rock VF effectively elevates the threshold cyclic stress ratio of the SRM, diminishes the Pore Water Pressure within the mixture, enhances the dynamic stiffness, and mitigates the cumulative strain. SRMs composed of rock shapes with increased angularity and reduced block sizes exhibit higher dynamic stiffness and cumulative strain. The threshold cyclic stress ratio for an SRM with a 40 % rock VF is approximately 0.04, and the pore pressure increment in the SRM exhibits a gradual change, which contrasts with the test outcomes for pure clay. The exponential-hyperbolic model provided a satisfactory fit for the pore pressure data, while the hyperbolic model yielded good fitting results for the cumulative strain of the SRM with a low rock VF. These findings contribute to an enhanced comprehension of the dynamic properties of railway subgrades filled with SRM under cyclic train loading conditions.</div></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":"51 ","pages":"Article 101539"},"PeriodicalIF":4.9000,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Transportation Geotechnics","FirstCategoryId":"5","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S2214391225000583","RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"ENGINEERING, CIVIL","Score":null,"Total":0}
引用次数: 0
Abstract
The microstructure of a soil–rock matrix (SRM) is a determinant of its macroscopic physical and mechanical attributes. The influence of the shape and volume fraction (VF) of rock blocks on the dynamic properties of the SRM has not been subjected to quantitative analysis. Consequently, a suitable construction technique was developed for the fabrication of small-scale triaxial specimens incorporating artificial rocks of various shapes. A series of homogeneous SRM specimens with differing rock VFs and shapes were fabricated. These specimens were then exposed to a long-term dynamic load consisting of 15,000 cycles at a frequency of 1 Hz. The principal findings are summarized as follows: The construction method proposed is capable of producing small artificial rocks with dimensions of 3 mm or 5 mm in arbitrary shapes while maintaining consistency with the prototypes. The method holds significant promise for application in geotechnical testing. Under long-term dynamic loading, the rock VF effectively elevates the threshold cyclic stress ratio of the SRM, diminishes the Pore Water Pressure within the mixture, enhances the dynamic stiffness, and mitigates the cumulative strain. SRMs composed of rock shapes with increased angularity and reduced block sizes exhibit higher dynamic stiffness and cumulative strain. The threshold cyclic stress ratio for an SRM with a 40 % rock VF is approximately 0.04, and the pore pressure increment in the SRM exhibits a gradual change, which contrasts with the test outcomes for pure clay. The exponential-hyperbolic model provided a satisfactory fit for the pore pressure data, while the hyperbolic model yielded good fitting results for the cumulative strain of the SRM with a low rock VF. These findings contribute to an enhanced comprehension of the dynamic properties of railway subgrades filled with SRM under cyclic train loading conditions.
期刊介绍:
Transportation Geotechnics is a journal dedicated to publishing high-quality, theoretical, and applied papers that cover all facets of geotechnics for transportation infrastructure such as roads, highways, railways, underground railways, airfields, and waterways. The journal places a special emphasis on case studies that present original work relevant to the sustainable construction of transportation infrastructure. The scope of topics it addresses includes the geotechnical properties of geomaterials for sustainable and rational design and construction, the behavior of compacted and stabilized geomaterials, the use of geosynthetics and reinforcement in constructed layers and interlayers, ground improvement and slope stability for transportation infrastructures, compaction technology and management, maintenance technology, the impact of climate, embankments for highways and high-speed trains, transition zones, dredging, underwater geotechnics for infrastructure purposes, and the modeling of multi-layered structures and supporting ground under dynamic and repeated loads.