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Experimental study and numerical modeling of crushing and mechanical behavior of rockfill materials : influence of particle size

Abstract : Crushing and mechanical behavior is one of the most important issues in the design and stability of rockfill constructions. The present thesis is devoted to experimental investigation and numerical modeling of this mechanism by putting the emphasis on the influences of particle size. It is composed of two parts: experimental investigation and numerical simulation. To investigate the particle size effect on the crushing and strength of rockfill particles, single-particle crushing tests are carried out on Shuangjiangkou rockfill materials with three particle sizes. The obtained particle strength decreases with increasing particle size and can be described by the Weibull distribution with the Weibull modulus of 3.29. The influence of particle size on the minimum and maximum dry densities of studied materials is also investigated by using dry density tests. Finally, the mechanical behavior of studied rockfill materials is studied via a series of triaxial compression tests. One observes that the stress-strain curves depend strongly on the particle size, for instance, the peak stress, the mobilized internal friction angle and the secant Young’s modulus increase with increasing maximum particle size dmax. The experimental results exhibit that the effects of particle sizes are related to the combinative effect of gradation and single particle strength. The numerical simulations are performed by using an open-source discrete element software, Yade. Firstly, the single-particle crushing tests are simulated to understand the micro-mechanisms of the particle size effects on breakage characteristics of rockfill materials. Numerical simulation results exhibit that the flaw volume ratio is the key issue of size effects on particle strength. After that, a new breakage criterion considering the effects of particle size is proposed. The formulation and implementation of proposed model and numerical method are first presented and discussed. Its efficiency in modelling the influence of particle size on the mechanical behavior of rockfill materials are then demonstrated. The emphasis is to put on the effects of particle size on the crushing patterns and deformation behavior. Comparisons between numerical results and experimental observations are presented.
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Submitted on : Monday, January 17, 2022 - 11:55:45 AM
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  • HAL Id : tel-03528523, version 1

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Xialong Zhao. Experimental study and numerical modeling of crushing and mechanical behavior of rockfill materials : influence of particle size. Civil Engineering. Université de Lille, 2021. English. ⟨NNT : 2021LILUI047⟩. ⟨tel-03528523⟩

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