CIVIL ENGINEERING |
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Particle flow simulations of the compaction of filling materials in highly filled foundation with analyses of the transverse isotropy |
ZHOU Mengjia, SONG Erxiang |
Department of Civil Engineering, Tsinghua University, Beijing 100084, China |
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Abstract Compaction is widely used in the construction of highly filled foundations with the filling material composed of a mixture of broken rock and soil. The rockfill usually comes from explosion and, thus, has irregular shapes. In addition, with the soil, the response of the broken rock-soil mixture during compaction differs from that of pure rockfill. This study simulates the compaction of highly filled foundations filled with broken rock-soil mixtures using the particle flow software PFC3D with the particles assumed to be elongated. Two other with pure rockfill with and without elongated rockfill particles were used to investigate the influence of particle shape and fine soil grains. The tamper response and the dynamic stress distribution in the soil were carefully studied and verified by field tests. The void ratio and the settling ratio predictions by the three models and the void ratio reduction are used to evaluate the models. Then, samples taken from foundations and triaxial tests are simulated with different orientation angles of the major principal stress to compare the soil properties before and after compaction. Finally, a static model is used to analyze the three-dimensional mesoscopic fabric to study the transverse isotropy of the soils after compaction. The results indicate that the broken rock-soil mixture with elongated rockfill particles is the best among the three models and that the soil behavior with elongated rockfill particles is cross-anisotropic after compaction with a larger modulus and higher peak strength in the vertical direction than in the horizontal direction. The soil simulations with spherical particles show that soil remains isotropic after compaction.
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Keywords
high filled foundation
dynamic compaction
PFC3D
transverse isotropy
mesoscopic fabric
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Issue Date: 15 December 2016
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