Strength and Deformation Behavior of Roadbed Aggregate by Large-Diameter Triaxial Test
Graded aggregates are widely used in the roadbed of high-speed railway, and its strength and deformation play a decisive role in determining the long-term service stability of railway. In this paper, aggregates with different gradation were tested by larg
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Introduction Graded aggregates are composed of aggregates which have different sizes. Graded aggregates are widely used in the roadbed of high-speed railway. Some scholars have studied the strength and deformation characteristics of graded aggregates. For the shear strength of graded aggregates, Yao [1] through large-diameter triaxial test to study in the condition of different confining pressure, degree of compaction, moisture state, and drainage condition, how the shear strength of graded aggregates behaviors, the experimental results show that the shear strength of graded aggregates increased with the increase of confining pressure and degree of compaction. Li and Li [2] also discuss the physical properties of graded aggregates and the factors which influence the mechanical properties of graded aggregates. In the construction of high-speed railway, local materials are often used to fill roadbed. Resulting in the gradation is often difficult to completely maintain the same. It is necessary to study the effect of gradation on the graded aggregates. But there is a lack of accumulation of large-diameter triaxial test result, it is difficult to form a unified and in-depth understanding. At the same time, in the actual engineering, some gravel in the foundation part of the subgrade is often broken by the upper load, which leads to the decline of the bed performance. The study of the crushing deformation of graded crushed stone is rare in the literature.
D. Sun (&) X. Bian W. Li Department of Civil Engineering, Zhejiang University, Hangzhou 310058, China e-mail: [email protected] X. Bian e-mail: [email protected] W. Li e-mail: [email protected] © Springer Nature Singapore Pte. Ltd. and Zhejiang University Press 2018 X. Bian et al. (eds.), Environmental Vibrations and Transportation Geodynamics, DOI 10.1007/978-981-10-4508-0_9
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Anderson and Fair [3] proposed a method to quantify particle breakage and a conceptual model to explain the combined effects of shearing and breakage on observed specimen behavior. Indraratna et al. [4] performed a series of static triaxial tests on ballast and found that ballast particles’ breakage is related to the deviator stress, the confining pressure and the excessive interaction between angular particles, while the friction angle of ballast decreases with the increase of confining pressure. The large-diameter triaxial tests are carried out on two typical graded aggregates and two single-size gravels, to study the effects of different gradations, different densities, different loads (confining pressure and axial loading) on the strength and deformation characteristics of graded aggregates. Particle breakage and its corresponding volume strain behavior are also discussed.
Test Apparatus Figure 1 shows the TAJ-2000 large-diameter triaxial testing apparatus utilized in this study. The test apparatus are mainly composed of six parts: the triaxial chamber, axial loading device, confining pressure boosting system, servo oil sources, loading control system, and corresponding dat
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