Experimental and simulation study on influence of pick cone angle on coal-rock fragmentation and dust-generation characteristics

doi:10.16265/j.cnki.issn1003-3033.2026.05.1249

Abstract

Abstract:

To investigate the influence of pick cone angle on coal-rock fragmentation and dust generation characteristics during underground roadheading operations, a multi-scale integrated approach combining experimental tests and discrete element method (DEM) simulations was adopted. Four picks with cone angles of 78, 92, 105 and 118° were selected as research objects. Roadheading cutting tests were conducted to analyze the particle size distribution of generated debris and dust. DEM simulations using the PBM in Particle Flow Code (PFC) software accurately reproduced the entire process of coal-rock fragmentation and dust generation during roadheading. The evolution trends of crack quantity, crack type, number of minimum-sized discrete particles, and ejection velocity were analyzed under two operational modes of the cutting head: penetration and slewing. The results indicate that as the cone angle increases, the coarseness index (CI) of coal wall debris decreases from 728.92 to 696.91, while the dust proportion increases from 0.4% to 0.67%, demonstrating that the degree of coal wall fragmentation and dust generation increases with pick cone angle. The fragmentation index rises and the uniformity index declines, indicating a broader dust particle size distribution and a higher proportion of fine dust particles. Simulation results show that the total number of cracks on the coal wall increases from 22 980 to 27 272, with tensile cracks consistently accounting for over 73% of the total. The number of minimum-sized free particles increases from 371 to 459, and their average initial ejection velocity decreases from 0.250 m/s to 0.221 m/s. In summary, increasing the pick cone angle intensifies dust generation to a certain extent, but helps suppress the dispersion range of dust.

Key words: cone angle of pick, dust generation from fragmentation, particle size distribution, parallel bond model (PBM), ejection velocity

CLC Number:

X936

Jing Deji, Dong Zhibin, Wang Deji, Li Zhen, Liu Hongwei, Bao Chunhua. Experimental and simulation study on influence of pick cone angle on coal-rock fragmentation and dust-generation characteristics[J]. China Safety Science Journal, 2026, 36(5): 64-72.

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粒径	筛余率/%
粒径	78°	92°	105°	118°
>20 mm	60.30	54.36	54.58	48.89
10~20 mm	82.19	76.87	77.59	71.56
0.85~10 mm	93.17	91.13	86.85	89.33
0.3~0.85 mm	96.54	96.02	92.91	93.46
0.18~0.3 mm	98.07	97.88	96.98	96.24
0.125~0.18 mm	99.05	98.77	98.50	98.10
75~125 μm	99.60	99.53	99.46	99.33
<75 μm	100.00	100.00	100.00	100.00
CI	728.92	714.56	706.87	696.91

粒径/μm	78°	92°	105°	118°
0	100.00	100.00	100.00	100.00
15	94.20	93.55	92.75	92.07
25	80.06	82.92	83.00	81.21
35	73.19	70.04	69.22	71.07
45	58.48	61.84	57.36	56.64
55	46.39	47.32	50.79	46.18
65	33.70	32.55	31.47	31.66
75	0.00	0.00	0.00	0.00

锥角/(°)	a	s
78	0.000 386 172	1.903 60
92	0.000 437 865	1.866 87
105	0.000 573 615	1.801 85
118	0.000 696 210	1.760 67

类别	单轴抗压强度/MPa	抗拉强度/MPa	弹性模量/GPa
物理试验	19.39	2.35	2.74
仿真标定	19.55	2.50	2.82

锥角/(°)	工况	数量/颗	总计
78	钻入	171	371
78	横摆	200	371
92	钻入	193	424
92	横摆	231	424
105	钻入	208	453
105	横摆	245	453
118	钻入	212	459
118	横摆	247	459