柔性隔離層下多漏斗散體礦巖力鏈演化特征的離散元模擬

陳慶發; 王少平; 秦世康

doi:10.13374/j.issn2095-9389.2019.10.03.001

柔性隔離層下多漏斗散體礦巖力鏈演化特征的離散元模擬

doi: 10.13374/j.issn2095-9389.2019.10.03.001

陳慶發^{1, 2, ,},
王少平²,
秦世康¹

1.
廣西大學資源環境與材料學院，南寧 530004
2.
廣西大學土木建筑工程學院，南寧 530004

基金項目: 國家自然科學基金資助項目(51964003，51464005)

詳細信息

通訊作者:
E-mail: chqf98121@163.com

中圖分類號: TD801
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- HTML全文瀏覽量: 707
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- 被引次數: 0
出版歷程
- 收稿日期: 2019-10-03
- 刊出日期: 2020-09-20

Discrete element simulation for evolution characteristics of multi-funnel mineral-rock force chain under flexible isolation layer

1.
College of Resources, Environment and Materials, Guangxi University, Nanning 530004, China
2.
College of Civil Engineering, Guangxi University, Nanning 530004, China

More Information

Corresponding author: E-mail: chqf98121@163.com

摘要

摘要: 為進一步揭示柔性隔離層下散體介質流動過程的內部作用機理，基于離散元軟件PFC開展了柔性隔離層下散體介質流力鏈演化特征的數值試驗研究。結合接觸力學及統計力學相關知識，對多漏斗放礦過程中散體介質體系內力鏈長度、數量、強度、方向和準直系數等的演化特征進行了量化研究。研究發現：多漏斗放礦過程中，強接觸及力鏈接觸占比均比較穩定，其中強接觸占比穩定在33%左右，力鏈接觸占比穩定在16%左右，上下波動幅度均不超過2%；力鏈總數隨著放礦次數的增加不斷波動減少，并在放礦后期穩定在790條左右；不同放礦次數下力鏈長度的概率分布幾乎一致，均隨著力鏈長度的增加呈指數形式遞減；力鏈強度的概率分布隨著放礦次數的增加先呈指數形式上升再呈指數形式下降，并在0.7$\bar F$（$\bar F$為平均接觸力）處出現一峰值；放礦初始階段，力鏈主要沿鉛垂方向分布，力鏈方向分布形態近似花生狀；此后隨著礦石顆粒的持續放出，散體介質體系內部局部應力集中現象明顯，力鏈分布主方向由1個演變為4個（鉛垂方向、水平方向及與水平方向呈±60°夾角方向）；力鏈準直系數隨著放礦次數的增加呈指數形式增長并逐漸保持穩定。
- 柔性隔離層 /
- 散體介質 /
- 力鏈 /
- 同步充填 /
- 離散元 /
- 流動規律
Abstract: To further reveal the internal mechanism of the granular media flow process under the flexible isolation layer, numerical experiments on the evolution characteristics of bulk media flow force chain under the flexible isolation layer were carried out based on the discrete element software PFC. Based on a combination of contact mechanics and statistical mechanics, the evolution characteristics of the force chain length, quantity, strength, direction, and the collimation coefficient of the internal bulk medium system in the multi-funnel ore drawing process were quantitatively studied. It is found that the proportions of the strong contact and the force chain contact is found to be relatively stable in the multi-funnel ore drawing process; the proportion of strong contact is stable at about 33%, that of the force chain contact is stable at about 16%, and the fluctuation amplitude is not more than 2%. The total number of force chains decreases with the increase in ore drawing times, and it is stable at 790 strips in the later stage of ore drawing. The probability distribution of the force chain length is almost the same under different ore drawing times, and it decreases exponentially with the increase in the force chain length. The probability distribution of the force chain strength first increases exponentially with the increase in the ore drawing times and then decreases exponentially; it reaches a peak value at 0.7$\bar F$ ($\bar F$ is the average contact force). In the initial ore drawing stage, the force chain is mainly distributed along the vertical direction, and the force chain direction distribution is similar to a peanut shape. After that, with the continuous release of ore particles, the phenomenon of local stress concentration in the granular media system becomes remarkable, and the main direction of the force chain distribution changes to become four (vertical direction, horizontal direction, and angles of ±60° to the horizontal). The force chain collimation coefficient increases exponentially with the increase in drawing times and gradually becomes stable.
- flexible isolation layer /
- granular media /
- force chain /
- synchronous filling /
- discrete element /
- flow law

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圖 1 數值試驗中的顆粒模型

Figure 1. Model of particles in the test

下載: 全尺寸圖片幻燈片

圖 2 力鏈宏觀分布特征

Figure 2. Macroscopic distribution characteristics of the force chain

下載: 全尺寸圖片幻燈片

圖 3 多漏斗放礦過程強接觸與力鏈接觸占比

Figure 3. Proportion of strong contact and force chain contact in multi-funnel ore drawing process

下載: 全尺寸圖片幻燈片

圖 4 多漏斗放礦過程散體介質體系內力鏈數目變化規律

Figure 4. Variation law of the number of force chains in the granular medium system during multi-funnel ore drawing

下載: 全尺寸圖片幻燈片

圖 5 多漏斗放礦過程力鏈長度概率分布

Figure 5. Probability distribution of the force chain length in the multi-funnel ore drawing process

下載: 全尺寸圖片幻燈片

圖 6 不同長度力鏈的概率分布

Figure 6. Probability distribution of force chains of different lengths

下載: 全尺寸圖片幻燈片

圖 7 多漏斗放礦過程力鏈強度演化規律

Figure 7. Evolution law of the force chain strength in the multi-funnel ore drawing process

下載: 全尺寸圖片幻燈片

圖 8 多漏斗放礦力鏈強度的概率分布

Figure 8. Probability distribution of the force chain strength in the multi-funnel ore drawing process

下載: 全尺寸圖片幻燈片

圖 9 多漏斗放礦過程力鏈方向演化規律

Figure 9. Evolution law of the force chain direction in the multi-funnel ore drawing process

下載: 全尺寸圖片幻燈片

圖 10 力鏈準直系數變化規律

Figure 10. Change law of collimation coefficient of the force chain

下載: 全尺寸圖片幻燈片

表 1 墻體及初始礦石顆粒力學參數

Table 1. Mechanical parameters of walls and initial ore particles

Walls			Initial ore particles
Shear stiffness / (N·m^?1)	Normal stiffness / (N·m^?1)	Friction coefficient	Normal stiffness / (N·m^?1)	Shear stiffness / (N·m^?1)	Friction coefficient	Ore particle density / (kg·m^?3)	Ore particle radius/m
1×10⁷	1×10⁷	0.5	5×10⁷	5×10⁷	0.3	2800	0.008

下載: 導出CSV

表 2 隔離層相關參數

Table 2. Parameters related to the isolation layer

Shear stiffness / (N·m^?1)	Normal stiffness / (N·m^?1)	Parallel bonding normal stiffness/ (N·m^?1)	Parallel bonding shear stiffness / (N·m^?1)	Ore particle density / (kg·m^?3)	Friction coefficient	Elastic modulus of parallel bond /Pa	Ore particle radius /m
1×10⁷	1×10⁷	1×10⁶	1×10⁶	2000	0.4	5×10⁷	0.0015

下載: 導出CSV

表 3 礦石顆粒參數

Table 3. Parameters of ore particles

Shear stiffness / (N·m^?1)	Normal stiffness / (N·m^?1)	Friction coefficient	Linear friction coefficient against rolling	Ore particle density / (kg·m^?3)	Ore particle radius / m
5×10⁷	5×10⁷	0.5	0.5	2800	0.008

下載: 導出CSV

表 4 多漏斗放礦過程力鏈方向分布的擬合結果

Table 4. Fitting results of the force chain direction distribution in the multi-funnel ore drawing process

Ore drawing times	f₀	a_n	θ_n
1	1.00	0.30	94.58
2	1.00	0.30	91.48
3	1.00	0.36	87.35
4	1.00	0.42	92.90
5	1.00	0.40	88.42
6	1.00	0.42	90.59
7	1.00	0.38	88.20
8	1.00	0.35	82.32
9	1.00	0.36	87.91
10	1.00	0.27	95.02
11	1.00	0.46	79.60
12	1.00	0.49	79.55

下載: 導出CSV

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