Numerical Analysis of Loading Rate on Shear Strength of Blast Furnace Slag Fly Ash Mixture

Chenglong Wu, Jiming Liu, Wei Shi, Xiang Liu


Application of blast furnace slag fly ash mixture in geotechnical engineering has often encounter all kinds of dynamic problems, it's not only to consider the static strength of geotechnical material, but also to consider the impact of collision, vibration and blasting or other dynamic load. Then, according to the existed interior of large-scale direct shear test data, it’s corresponding large-scale direct shear test models was established by PFC3D, blast furnace slag fly ash mixture mechanical response, energy response and the contact force chain fields changes were analyzed under different loading rate. Results show: under different normal stress, the smaller the loading rate, the greater the peak intensity of the mix. The phenomenon of sample dilatation and stress softening was more obvious, and the longitudinal strain was higher with low confining pressure (500kPa) than the high (1200kPa). When the loading rate was 1~2mm/min, mixture strength parameters were larger than other loading rate. According to the energy response, the failure process of mixture was overcome the binding effect, and the bond micro cracks which were driven by strain energy were continue to expand, friction energy was gradually occupy the dominant. When the shear strength was reaches the peak, strain energy was tends to slow, while the friction was increase sharply. Contact force chain was fusiform shape after shear failure, especially when the shear rate of 2mm/min was more obvious, this was consistent with the 2mm/min shear rate in laboratory tests.


Loading Rate; PFC3D; Blast Furnace Slag; Fly Ash; Large Direct Shear Test


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