Fragment Size Distribution Research Articles

Experimental Study on the Size of Rock Fragments Ejected from Boreholes Drilled in Coal Mine Roadway Floors

Borehole drilling is required if floor heave in underground mines is to be controlled using bolts through the floor. How well the bolt is anchored depends, in part, on the borehole’s quality. A major factor that can reduce borehole quality is the difficulty of discharging rock fragments from a small-diameter borehole drilled at a downward angle. Therefore, a fuller understanding of the sizes of the rock fragments will aid attempts to achieve smooth fragment discharge. In this study, drilling experiments in the laboratory and SEM imaging were carried out to determine the size and shape of the fragments generated when drilling boreholes in three sedimentary rocks typically found in roadway floors. The results show that the size distribution of the rock fragments conformed to the three-parameter generalized extreme value distribution. The mean fragment size increased with rock density and the mean size of the fragments larger than 1.5 mm increased with the rock’s uniaxial compressive strength. The fractal dimension of the cracks in the fragments was lower for high-density rocks and the mean fragment size was larger for rocks whose cracks had a lower fractal dimension. When a drill rod drills through very dense or high-strength rock, the mean size of the fragments will increase and the discharge power should be increased to prevent fragment discharge blockages. This paper may provide a theoretical basis and a data reference for discharge power settings and discharge channel optimization.

High-velocity impact fragmentation of additively-manufactured metallic tubes

In this paper, we have developed and demonstrated a novel high-velocity impact experiment to study dynamic fragmentation of additively-manufactured metals. The experiment consists of a light-gas gun that fires a conical nosed cylindrical projectile, that impacts axially on a thin-walled cylindrical tube fabricated by 3D printing. The diameter of the cylindrical part of the projectile is approximately twice greater than the inner diameter of the cylindrical target, which is expanded as the projectile moves forward, and eventually breaks into fragments. The experiments have been performed for impact velocities ranging from ≈180m/s to ≈390m/s, leading to strain rates in the cylindrical target that vary between ≈9000s-1 and ≈23500s−1. The cylindrical samples tested are printed by Selective Laser Melting out of aluminum alloy AlSi10Mg, using two printing qualities, with two different outer diameters, 12 mm and 14 mm, and two different wall thicknesses, 1 mm and 2 mm. A salient feature of this work is that we have characterized by X-ray tomography the porous microstructure of selected specimens before testing. Three-dimensional analysis of the tomograms has shown that the initial void volume fraction of the printed cylinders varies between 1.9% and 6.1%, and the maximum equivalent diameter of the 10 largest pores ranges from 143μm to 216μm, for the two different printing conditions. Two high-speed cameras have been used to film the experiments and thus to obtain time-resolved information on the mechanics of formation and propagation of fractures. Moreover, fragments ejected from the samples have been recovered, sized, weighted and analyzed using X-ray tomography, so that we have obtained indications on the effect of porous microstructure, specimen dimensions and loading velocity on the number and distribution of fragment sizes. To the authors’ knowledge, this is the first paper (i) providing a systematic experimental study (34 impact tests) on the fragmentation behavior of printed specimens, and (ii) including 3D reconstructions of dynamic cracks in porous additively-manufactured materials.

Numerical investigation on rock fragmentation under decoupled charge blasting

Blasting using decoupled charge is extensively applied in rock excavation and rock fragmentation. In this study, the rock fragmentation induced by blasting using decoupled charge is investigated by combined finite element modelling and image-processing. After calibrating the numerical model developed in LS-DYNA against the fragment morphology and fragmentation size distribution (FSD) in three air-coupling blasts and three water-coupling blasts, a series of cubic single-hole models are constructed to simulate rock cracking induced by decoupled charge blasting with various decoupling ratios, distinct coupling mediums and different decoupled charge modes. The simulated fracture networks are obtained by blanking the damaged elements whose damage level is over the threshold of crack formation, and the resulting crack patterns are image-processed using ImageJ to identify fragment size. Then, the blast-created FSDs are characterized by a three-parameter generalized extreme value function, and the FSDs with decoupling ratios, coupling mediums and different decoupled charge modes are quantitatively analyzed and compared. The results show that rock fragmentation becomes finer and the FSD range gets narrower with the decrease in decoupling ratio. Meanwhile, smaller fragment sizes and narrower FSD spans are obtained when changing coupling material from air to water and altering radial decoupling to axial decoupling.

Solid State Material Driven Turbine to Reduce Segregation during Bunker Filling

For most applications and their following processes, an evenly distributed bunker outflow is desired in terms of particle size. Various discrete element simulations were performed to analyze the current state of an existing bunker used for storage of blast furnace sinter, which is simply filled with a discharging belt conveyor. Great segregation effects could be determined, which are mainly caused by the filling method and further intensified by the core flow effect and bunker geometry.Several concepts and devices to reduce segregation in bunkers were evaluated using DEM. The particle size distributions at the bunker outflow were each compared with the current state without a device. A solid state material driven turbine is presented, which reduces segregation effects during bunker filling and leads to a significant improvement during the discharge. The results show a more evenly distributed bunker outflow in terms of particle size.As sinter is a very abrasive material, the wear at the turbine has also been evaluated. Furthermore, the power output in this case and the potential of energy recovery were investigated, which could be of interest in many other applications.Additionally, the particle degradation at the solid state material driven turbine is evaluated in this case. A newly developed breakage model for DEM is used. The model is based on the particle replacement method, combined with the voronoi tessellation algorithm and breakage probabilities to achieve a high accuracy in terms of fragment size distribution.

The Influence of Fly Ash Contents on Mechanical Properties and Energy Response of Concrete at a High Strain Rate

The dynamic uniaxial impact compression test was carried out by the Hopkinson pressure bar test system to test the dynamic mechanical properties of concrete with different fly ash contents ( P = 0 , 10%, 20%, 30%, 40%, and 50%) under 0.3 MPa air pressure. The influences of fly ash content variation on the mechanical characteristics, ductility characteristics (which were calculated according to the concrete ductility formula), energy dissipation characteristics, and surface specific energy variation characteristics (which were calculated by converting the fragments into spheres) of concrete were analyzed, respectively, and the influences of fly ash content variation on the fragment distribution and fractal features of concrete were obtained by statistical analysis. In addition, the application of concrete with the change of fly ash contents in rock burst mine was studied. The results showed that the dynamic peak stress, residual stress, ductility characteristics, fragments distribution, fractal dimension, transmitted energy, dissipated energy, and surface specific energy change significantly with the increase of fly ash contents under dynamic uniaxial impact compression. By analyzing the relationship between surface specific energy and concrete fragment distribution, it could be found that the energy dissipated by stress waves in concrete can be estimated by using the particle size distribution of the field fragments.

An investigation on relations between dissipated energy and dynamic compressive strength of Kemi-peridotite at high strain rates

Dynamic properties of rocks are essential for planning sustainable engineering structures in regions prone to dynamic loading as well as effective fragment size distributions during quarrying activities. Due to the vast application of dynamic rock properties, several studies have been conducted on the context. However, studies on relations between dissipated energy and dynamic compressive strength are scanty. The aim of the study is to investigate relations between dynamic compressive strength and dissipated energy during fragmentation of Kemi-peridotites at high strain rates. To achieve this, cored specimen was prepared according to recommendations of the International Society for Rock Mechanics and fractured using the split Hopkinson’s pressure bar. Results indicate that the dissipated energy during rock fracture generally increases at high dynamic compressive stress. However, the regression square of dissipated energy and dynamic compressive strength plots suggest poor relations between both variables. Further evaluation of measured strain at maximum dynamic compressive stress indicates that strain in specimen continued significantly after maximum dynamic compressive stress was attained. However, evaluations on relations between dissipated energy and strain indicates that energy dissipation continued along a significant portion of the measured strain during rock fracture at high strain rates. Visual evaluation of broken fragments also indicates good relations between dissipated energy and fragmentation results of Kemi-peridotites at high strain rates. Based on study findings, dissipated energy provides improved indices for evaluating strain and fragment size distribution while dynamic compressive stress provides indices on maximum stress required for rock failure.

Rancangan geometri peledakan yang efisien untuk mendapatkan distribusi ukuran fragmentasi batu gamping

The rock fragmentation distribution resulting from blasting is one of the important factors of the blasting method design model for dismantling excavated materials. Calculation of rock fragmentation resulting from blasting using the R.L. Ash, C.J. Konya, and ICI-Explosive theories. The method for determining the size of rock fragmentation resulting from blasting and analysis of the fragmentation size distribution in blasting activities uses the Kuz-Ram method and Split Desktop 4.0 software. A good blasting geometry design from a technical and economical point of view enables achieving target production according to the design made by the company in producing an average fragmentation size of limestone <50 cm. Blasting geometry applied by PT. Semen Padang produces a hole volume of 275 m3 with a fragmentation of 53.46 cm. The results of the fragmentation design are based on the R.L. Ash theory and the Kuz-Ram method, with a volume of 300.67 m3 in each hole and a fragmentation size of 50.07 cm, while using C.J. Konya analysis resulted in a hole volume of 422.4 m3 with an average fragmentation of 44.17 cm, and ICI-Explosive method resulted in a hole volume of 285 m3 with an average fragmentation of 47.86 cm. Based on blasting geometry calculation, fragmentation analysis and economic calculations, it is shown that the blasting geometry suggestion using C.J. Konya theory is more optimal and feasible to apply because it results in a larger hole blasting volume, higher percentage of fragmentation of <50 cm which is compatible with the bucket capacity, as well as higher revenue and profit compared to the other two methods.

Dynamic compressive response and fracture mechanisms of ZrB2–SiC ceramic based on discrete element method

AbstractTo investigate the dynamic compression behaviors of fracturing and damage evolution of ZrB2–SiC ceramic, this paper proposes a discrete element method to carry out the dynamic compressive behavior of ZrB2–SiC ceramic. This study is based on three‐dimensional discrete element‐finite difference coupling modeling to realize the reproduction of the splitting Hopkinson pressure bar experiment process. Micro‐parameters of the linear parallel bond model are obtained by calibrating dynamic compression strengths, stress–strain curves, and fracture characteristics of ZrB2–SiC ceramic. The dynamic compressive stress–strain curve can be divided into four stages according to the microcrack evolution and acoustic emission: stage I, linear elastic stage; stage II, microcrack initiation and then stable development stage; stage III, increment stage of microcracks before peak strength; stage IV, increment stage of microcracks after peak strength. The dynamic damage evolution with strain shows a Weibull distribution. The shape and scale parameters change with strain rate. In addition, under the dynamic compression, crack initiation stress, fracture pattern, and fragment size distribution of the ZrB2–SiC ceramic composite exhibited a significant strain‐rate dependence.

Size distribution analysis of residual host cell DNA fragments in lentivirus by CGE-LIF.

During the production of cell and gene therapy products, residual host cell DNA (HCD) could cause safety risks of the biological products, and the longer the residual HCD fragment, the greater the risk to the human body. For this reason, it was necessary to develop an effective method for the size distribution analysis of residual HCD fragments with high accuracy and sensitivity. In this study, capillary gel electrophoresis with laser-induced fluorescence detector (CGE-LIF) was used to analyze the size distribution of residual HCD fragments in lentivirus products. The results confirmed that lentiviral RNA genome could interfere with the size distribution analysis of residual HCD fragments. By optimizing the amount of RNase I and digestion time in sample pretreatment process, the interfere of RNA genome could be avoided. The specificity, precision, accuracy, linear range, the detection of limit (LOD), and the quantification of limit (LOQ) of CGE-LIF method were also validated. The results showed that the CGE-LIF method had a good performance both in terms of specificity and reproducibility. The intra- and inter-day relative standard deviations of migration time and corrected peak area were all less than 1% and 2%, respectively. The 200bp DNA marker had a good linearity between 50 and 1000pg/ml. The LOD and LOQ of 200bp DNA marker were 2.59 and 8.64pg/ml, respectively. In addition, this method was successfully used to analyze the size distribution analysis of residual HCD fragments in lentivirus products with different production processes.

Reconstruction of dynamics processes of Tagharma rock avalanche in Pamir Plateau: Geomorphology and sedimentology implications

Rock avalanches are characterized by granular flows of dry and disintegrating rock masses detached from a mountain slope. They deposit large volumes of megablocks, which have distinct surface features and are known to cause catastrophic damage. The mechanisms and dynamic processes of such disasters are still under debate, owing to insufficient real-time data. Here, field surveys and high-resolution digital elevation models (DEMs) were used to investigate the dynamic processes of the Tagharma rock avalanche (Kongur Mountain, Eastern Pamir, China), providing a unique case study for determining the long runout mechanisms and dynamic processes of the avalanche based on its morphology and sedimentology. The processes and dynamics of the event were reconstructed through fragmented rock debris combined with surface morphology and substrate implications. We analyzed how fragmentation occurs at impact and studied the generated fragment size distributions. Finally, the emplacement dynamics of the Tagharma rock avalanche were reconstructed. Our results indicate that the dynamic process of the Tagharma rock avalanche consisted of two main stages: (i) foliated megablocks having a strong interaction between the rock avalanche mass and the ground (dynamic rock mass disintegration), and (ii) distal “passive spreading” when the avalanche mass encountered deformable substrates (sediment bulldozing).

On the Dynamic Fragmentation of Rock-Like Spheres: Insights into Fragment Distribution and Energy Partition

Fragmentation of blocks upon impact is commonly observed during rockfall events. Nevertheless, fragmentation is not properly taken into account in the design of protection structures because it is still poorly understood. This paper presents an extensive and rigorous experimental campaign that aims at bringing insights into the understanding of the complex phenomenon of rock fragmentation upon impact. A total of 114 drop tests were conducted with four diameters (50, 75, 100, and 200 mm) of rock-like spheres (made of mortar) of three different strengths (34, 23 and 13 MPa), falling on a horizontal concrete slab, with the objective to gather high-quality fragmentation data. The analysis focuses on the fragment size distribution, the energy dissipation mechanisms at impact and the distribution of energy amongst fragments after impact. The results show that the fragment size distributions obtained in this campaign are not linear on a logarithmic scale. The total normalised amount of energy loss during the impact increases with impact velocity, and consequently the total kinetic energy after impact decreases. It was also found that energy loss to create the fracture surfaces is a constant fraction of the kinetic energy before impact. The trajectories of fragments are related to the impact velocity. At low impact velocity, the fragments tend to bounce but, as the impact velocity increases, they tend to be ejected sideways. Although testing mortar spheres in normal impact is a simplification, the series of tests presented in this work has brought some valuable understanding into the fragmentation phenomenon of rockfalls.

An uncertainty hybrid model for risk assessment and prediction of blast-induced rock mass fragmentation

Blasting is an important mining operation that usually produce several damaging consequences. Adverse rock fragmentation due to bench blasting is one of them. Hence, analysis of risk level and accurate estimation of particle size distribution of fragment size are of interest. This research developed a new model to simultaneously predict and risk assessment of rock fragmentation using 64 collected data from blasting operated in the Zarshouran gold mine in Iran. In this regard, a newly rock engineering system (RES) is developed based on the reliability information of Z-number theory and causal-effect relationship of the fuzzy cognitive map (FCM). This approach is named the reliability rock engineering causality system (RRECS). To do this, 15 principal effective parameters on rock fragment size were considered in the RRECS modeling process. The uncertainty of the interaction matrix was reduced using Z-number concept. Besides, the weight of effective parameters updated based on the combination of the nonlinear Hebbian algorithm (NLH) and differential evolution algorithm (DE) in FCM. The RRECS performance was validated by statistical linear and non-linear models. The results show R2, RSME, BIAS, and Accuracy using the proposed RRECS model calculated to be 0.957, 1.956, 0.001, and 96.741 for training and 0.931, 0.996, 0.016, and 99.053 for testing parts, respectively. Therefore, RRECS has performed better than the exponential, power, logarithmic, polynomial, and linear models. Furthermore, the sensitivity analysis results revealed that the hole diameter and powder factor parameters have the highest and lowest sensitivity on fragmentation, respectively.

Associations of genome-wide cell-free DNA fragmentation profiles with blood biochemical and hematological parameters in healthy individuals

Cell-free DNA (cfDNA), as a non-invasive approach, has been introduced in a wide range of applications, including cancer diagnosis/ monitoring, prenatal testing, and transplantation monitoring. Yet, studies of cfDNA fragmentomics in physiological conditions are lacking. In this study, we aim to explore the correlation of fragmentation patterns of cfDNA with blood biochemical and hematological parameters in healthy individuals. We addressed the impact of physiological variables and abnormal blood biochemical and hematological parameters on cfDNA fragment size distribution. We also figured and validated that hematological inflammation markers, including leukocyte, lymphocyte, neutrophil, and platelet distribution width as well as aspartate transaminase levels were significantly correlated with the genome-wide cfDNA fragmentation pattern. Our findings suggest that cfDNA fragmentation profiles were associated with physiological parameters related to cardiovascular risk factors, inflammatory response and hepatocyte injury, which may provide insights for further research on the potential role of cfDNA fragmentation in diagnosis and monitor of several disease.

In situ measurement of the fragmentation behavior of Al/PTFE reactive materials subjected to explosive loading, Part 1: Fragment size measurements

AbstractHigh‐speed optical diagnostics and image analysis methods are applied here to measure the size, velocity, and trajectory of Al/PTFE fragments produced by explosively loading cylindrical specimens. The imaging utilizes high‐speed digital cameras and focused shadowgraphy to capture time‐resolved images of the accelerated fragment field. In Part 1, high‐fidelity fragment size distributions are measured from visual timelines assembled from the high‐speed images through a phase correlation stitching process. The in situ measurements are compared to fragment size distributions measured from images of fragments recovered using a traditional snow soft catch. The two methods show similar size distributions, with the in situ measurement capturing essentially all of the fragment mass whereas the soft catch recovered less than 70 % of the initial sample mass. The fragment mass‐size distributions were fit to a fragmentation model. The model fit showed consistency across tests and a value of the scaling parameter approximately equal to the proposed universal value. In Part 2, a two‐dimensional Kalman filter‐based automated tracking methodology is presented that is used to determine trajectories and velocities of fragments greater than 1 mm. The measured velocities are compared to velocity estimates from the bulk fragment displacement calculated using a phase correlation routine. Bivariate histograms describing the diameter‐velocity variations are presented for the explosive fragmentation and acceleration of these Al/PTFE samples.

Dynamic Split Tensile Strength of Basalt, Granite, Marble and Sandstone: Strain Rate Dependency and Fragmentation

The aim of this study is to understand the strength behaviour and fragment size of rocks during indirect, quasi-static and dynamic tensile tests. Four rocks with different lithological characteristics, namely: basalt, granite, sandstone, and marble were selected for this study. Brazilian disc experiments were performed over a range of strain rates from ~ 10–5 /s to 2.7 × 101 /s using a hydraulic loading frame and a split Hopkinson bar. Over the range of strain rates, our measurements of dynamic strength increase are in good agreement with the universal theoretical scaling relationship of (Kimberley et al., Acta Mater 61:3509–3521, 2013). Dynamic fragmentation during split tension mode failure has received little attention, and in the present study, we determine the fragment size distribution based on the experimentally fragmented specimens. The fragments fall into two distinct groups based on the nature of failure: coarser primary fragments, and finer secondary fragments. The degree of fragmentation is assessed in terms of characteristic strain rate and is compared with existing theoretical tensile fragmentation models. The average size of the secondary fragments has a strong strain rate dependency over the entire testing range, while the primary fragment size is less sensitive at lower strain rates. Marble and sandstone are found to generate more pulverised secondary debris when compared to basalt and granite. Furthermore, the mean fragment sizes of primary and secondary fragments are well described by a power-law function of strain rate.

Modeling uniform random distributions of nonwoven fibers for computational analysis of composite materials

This paper considers the random placement of fibers on a square to achieve a desired homogeneous uniform distribution, as required in production of digital twin geometry for computational analysis of composite materials. Six methods of random fiber placement were demonstrated. Bertrand’s paradox for placement of random chords on a circle provided the framework to compare, contrast, and evaluate similar methods for placing fibers on a square. Simulations were performed with chord placement on a circle and fiber placement on a square. Results were evaluated using uniformity of areal line density and fragment size distributions. A combined approach for placement of fibers on a square was developed that achieved homogeneous uniform distribution. A proposed exact solution to achieve the desired uniform distribution was demonstrated. A statistical analysis and data regression demonstrated the homogeneous results achieved by the combined approach and the proposed exact solution. The objectives of this paper were achieved through demonstration of both a combined approach and a proposed exact solution to random fiber placement on a square to achieve homogeneous, uniform distribution of fibers for use in digital twin geometry for computational testing of composite materials.

Exploring effects of property variation on fragmentation of metal rings using a simple model

A simple finite element implementation of the Mott model for fragmentation of a thin walled ring has been implemented and used to explore the effect of local variations in fracture strain around the ring. The model has successfully reproduced the fragment size distributions previously reported, which follow a characteristic “Mott distribution” form, providing sufficient (1000) simulations are run. It has been shown that this form is retained even when there are large differences in the random distribution of fracture strains or a different choice of function used to describe the fracture strain scatter. In these cases, the strain rate has a much stronger effect than fracture strain distribution the on the average fragment size and fragment distribution. However, for cases where there are a small number of local defects that strongly reduce the fracture strain at certain locations around the ring, the predicted fragment size distribution develops a bimodal character. This is also the case for large but gradual variations in fracture strain with position around the ring. The results have implications for cases where a small number of large pre-existing defects exist, or processing has led to macrozones in the microstructure. The utility of a simple fast running model to study these cases is discussed.

Collisions between liquid droplets during the intersection of aerosol flows in a heated gas

• A rise in the gas temperature led to an increase in the number of secondary fragments. • At T g = 300–400 °C droplets with r d = 0.075–0.1 mm prevail. • A temperature rise contributed to a 2–3 times increase in area ratios S 1 / S 0. • At T g = 100–400 °C, droplets increased in size due to expansion of liquid on heating. • The motion of droplets in a heated gas led to a 10–30% change in their size due to evaporation. The paper presents the experimental findings on the water droplet collision behavior during the intersection of two aerosol flows in a high-temperature gas environment. Aerosol flows were produced by two strip pattern nozzles angled at 45° towards each other in the same plane. The resulting flow had an opening angle of 60°. The droplet impact angle (α d ) was varied from 0 to 90°, droplet radii ( R d1 , R d2 ) from 0.1 to 1.2 mm, and droplet velocities ( U d1 , U d2 ) from 2 to 12 m/s. The gas temperature in the droplet collision zone was varied using an induction heater with an internal volume of about 0.13 m 3 with viewing windows to record the key parameters (number, size, velocities, and trajectories) of liquid fragments before and after collision. The air temperature ranged from 20 to 400 °C in the experiments. Using a high-speed video camera, we recorded four collision regimes: coalescence, separation, disruption, and bounce. We also identified the main differences in the number and size of secondary droplets formed in an aerosol flow after the collision of two primary ones. A temperature rise led to an increase in the number of secondary fragments. The size distributions of secondary fragments are presented for three ranges of size ratios of initial droplets: Δ < 0.3; 0.3 < Δ < 0.7; Δ > 0.7. The impact of droplet collisions on their size variation rates was estimated at the gas temperature T g = 20–400 °C. Finally, we compared the contribution of this factor and evaporation without droplet-droplet collisions.

EP01.01-011 Utility of Arm-level cfDNA Fragment Size Distribution in the Early Detection of Lung Cancer and Pan Cancer

Lung cancer has the highest incidence and mortality worldwide. Early detection of lung cancer is critical for improving the prognosis of patients. cfDNA fragmentomics has shown a potential in the detection of lung cancer; however, existing predictive models lack of extensive cross-study validation, and the robustness and generalizability of the features and models should be tested and improved.

Analysis of slope fracturing under transient earthquake loading by random discrete element method

Earthquake can cause significant rock fracturing in either the short or long terms. A comprehensive analysis of the fracturing mechanism is critical for assessing the risks of potential slope failures, landslides and rock avalanches in seismic prone areas. This study employed 2D discrete element method (DEM) to investigate the fracturing of an intact rock slope of 600 m in base length and 300 m in height, with explicit considerations of material heterogeneity by random field theory. A total of 5400 DEM simulations were performed, and the characteristics of slope fracturing were statistically analysed. The dynamic loading by earthquake has triggered significant amplifications of ground motion and slope damage at the slope crest, resulting in densely spaced and interconnect fractures. These fractures split the slope into a collection of rock fragments with varied shapes, and the fragment size followed the Weibull's cumulative distribution. More than 70% of generated fragments were finer than 0.1 times the initial slope size, while only few large fragments existed at the slope base. The fragment size distribution pattern could quantitatively agree with field observations. The distributions of final slope damage index and cumulated fragmentation energy all followed the normal distribution pattern. The overall bulk seismic energy input into the slope was dissipated mainly at discontinuities and decreased with the increase of slope inclination. • Differential ground displacements exist widely within the slope, which is critical for earthquake induced fractures. • The sizes of the generated rock fragments follow well the Weibull's cumulative distribution. • Statistically, the slope damage index and fragmentation energy all follow the normal distribution pattern. • The slope damage intensity decreases with the increase of slope inclination angle.