Fractal Pattern of Particle Crushing of Granular Geomaterials during One-Dimensional Compression

Abstract

This paper focuses on the effect of particle crushing on the behavior of granular geomaterials. Series of high-pressure one-dimensional compression tests were carried out on a quartz sand-gravel. A detail investigation was performed primarily on the compression behavior, the evolution of particle-size distribution (PSD), the fractal pattern of the grading curve, and the amount of particle crushing. It was found that both the yielding state and the state at the maximum compressibility are closely associated with the evolution of PSD and the fractal pattern of particle crushing. As the vertical stress increases, the fractal characteristic of the grading curve appears only within the finer part at first, evolves into bifractal within the overall measurable grading curve late, and translates into monofractal finally. Furthermore, a pair of particle crushing indexes Be1 and Be2 considering different particle size scales were proposed. The reasonability of using Be1 and Be2 to describe the amount of crushing corresponding to the scale of particles was discussed. Finally, it was found that the value of the ratio between the volumetric strain and the crushing index Be1 is constant and independent of the initial particle size and the initial PSD when the vertical stress is larger than the stress at the maximum compressibility or the coarser part of the grading curve is evolved into fractal.

The Constitutive Model of Rockfill Based on Property‐Dependent Plastic Potential Theory for Geomaterials

“…erefore, it is important to study the mechanical properties of rockfill materials by quantitatively describing its gradation of rockfill materials which approaches the true properties and status of raw materials. Zhang and Zhang [25] found that the particle yield and compression state were closely related to the particle-size distribution and fractal curve characteristics of particle breakage through a one-dimensional compression test. Besides, the study found that the fractal dimension D could be used to describe the rockfill particle-size distribution.…”

“…where η c is the stress ratio under the critical state. According to the energy relationship of the critical state given in equation (25), the dilatancy equation based on the potential theory related to material properties could be obtained as follows:…”

“…where the main strain was determined by property-dependent plastic potential theory in equation (25). Assuming (q/p) � η, equation ( 29) could be rearranged as…”

Train Moving Load‐Induced Vertical Superimposed Stress at Ballasted Railway Tracks

“…As a result, the trapezoidal method significantly overestimated the vertical stress in comparison with the field measurement [5,8]. In addition, the ballast aggregates subjected to the cycle train loading, resulting in considerable ballast fouling, such as particle degradation, infiltration of fines from surface, subballast and subgrade infiltration, and weathering factors [2,3,[9][10][11][12][13][14][15][16][17][18][19][20][21]. erefore, the properties of ballast (the internal friction angle of ballast (φ B ) and maximum particle size (D max )) and stress distribution in substructure significantly varied with the real situations in practice [22][23][24].…”

Experimental Investigation of Sand Subjected to High Stress Levels in Wet and Dry Conditions

“…Many experimental studies have already examined the effect of initial void ratio [ 5 ], particle size [ 6 , 7 , 8 ] and angularity [ 9 , 10 , 11 ], relative density [ 12 , 13 ], material composition [ 14 , 15 ], and saturation degree [ 16 , 17 , 18 ] on particle crushing and thus on soils’ behavior [ 19 ]. The studies of the behavior of sand media at low to intermediate levels of stress are plentiful, but are limited for compression tests at high levels of stress (some tens to some hundreds of MPa).…”