CFRP布均匀约束煤圆柱轴压性能

李庆文; 胡露露; 曹行; 曾杏钢; 高森林; 祝青云; 刘艺伟; 禹萌萌; 黄筱

doi:10.13801/j.cnki.fhclxb.20211201.001

CFRP布均匀约束煤圆柱轴压性能

doi: 10.13801/j.cnki.fhclxb.20211201.001

辽宁工业大学　土木建筑工程学院，锦州 121001

基金项目: 国家自然科学基金(51704144)；辽宁省博士科研启动基金(2019-BS-120)；辽宁省自然科学基金指导项目(20180550297)

详细信息

通讯作者:
李庆文，博士，讲师，硕士生导师，研究方向为新材料与新型组合结构及离散元-有限元耦合细观模拟　E-mail: lgjzlqw@163.com

中图分类号: TU398
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- 被引次数: 0
出版历程
- 收稿日期: 2021-10-19
- 修回日期: 2021-11-10
- 录用日期: 2021-11-24
- 网络出版日期: 2021-12-02
- 刊出日期: 2022-11-01

Axial compressive behavior of CFRP uniformly wrapped coal in circular columns

School of Civil and Architectural Engineering, Liaoning University of Technology, Jinzhou 121001, China

摘要

摘要: 为扩大纤维增强树脂复合材料(FRP)加固组合结构的应用范围，改善煤矿采空区煤柱的承载能力和变形能力，对碳纤维增强树脂复合材料(CFRP)均匀约束煤圆柱的轴压性能进行了研究。试验结果表明：因CFRP的均匀约束，致使煤圆柱破坏时基本保持原状，断口位置约为0.25~0.5倍煤样高度范围，轴向变形能力至少提高1.5倍；单、双层CFRP约束煤圆柱的峰值强度分别提高了3.56~6.34倍、6.33~11.21倍；相同CFRP布层数时，随加载速率的增大，CFRP约束煤圆柱的强度增强比则逐渐降低，且CFRP层数越多，降低趋势越显著；CFRP层数对峰值强度的影响要比加载速率对峰值强度的影响更显著，加载速率对破坏时间的影响要比CFRP层数对破坏时间的影响更显著。获得了兼顾加载速率与CFRP层数的强度增强比三维可视化映射函数；建立了CFRP布约束煤圆柱的修正Richart强度分析模型，整体绝对误差评价指标表明模型性能优越，精度较高。
- CFRP /
- 均匀约束 /
- 约束煤圆柱 /
- 强度增强比 /
- 强度模型
Abstract: To facilitate the practical application of fiber-reinforced polymer (FRP) strengthened structures and improve the bearing capacity and deformation capacity of coal pillar in goaf, the mechanical performance of carbon fiber-reinforced polymer (CFRP) uniformly wrapped coal columns under axial compression was explored. Test results show that its state is basically unchanged and the fracture position is about 0.25-0.5 times the height of CFRP confined coal columns, and the axial deformation capacity is increased by at least 1.5 times when the coal columns are damaged since the uniform confinement of CFRP. The peak strength of single and double CFRP confined coal columns is increased by 3.56-6.34 times and 6.33-11.21 times, respectively. When the number of CFRP layers is the same, the strength enhancement ratio of CFRP confined coal columns decreases gradually with the increase of loading rate, and the decrease trend becomes more significant with the increase of the number of CFRP layers. The effect of CFRP layers on peak strength is more significant than that of loading rate, but it is obviously the opposite as for the failure time. It has been obtained that the 3D visualized mapping function of strength enhancement ratio considering loading rate and number of CFRP layers. The modified Richart strength model of CFRP confined coal columns has been established, and the index of integral absolute error shows that the model has good performance and higher precision.
- CFRP /
- uniform confinement /
- confined coal columns /
- strength enhancement ratio /
- strength model

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图 1 CFRP约束煤样制备

Figure 1. Preparation of CFRP confined coal specimens

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图 2 CFRP拉伸试验

Figure 2. Tensile test of CFRP coupons

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图 3 CFRP荷载-应变曲线

Figure 3. Tensile load-axial strain curves of CFRP sheets

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图 4 CFRP约束煤样轴压试验加载及测量装置

Figure 4. Axial compression test loading and measuring device of CFRP confined coal specimen

H1, H2, H3, H4—Hoop strain gauge of different angles; S1, S2—Axial strain gauge

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图 5 未约束煤样应力-应变曲线

Figure 5. Stress-strain curves of unconfined coal specimens

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图 6 CFRP约束煤样应力-应变曲线

Figure 6. Stress-strain curves of CFRP confined coal specimens

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图 7 CFRP布约束煤圆柱峰值强度与加载速率关系

Figure 7. Relation between peak strength and loading rate of CFRP confined coal columns

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图 8 CFRP布约束煤圆柱峰值强度三维曲面

Figure 8. 3D surface of peak strength of CFRP confined coal columns

R²—Coefficient of determination

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图 9 CFRP布约束煤圆柱破坏时间-CFRP层数关系

Figure 9. Relationship between failure time and CFRP layers of CFRP confined coal columns

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图 10 CFRP布约束煤圆柱破坏时间三维函数曲面

Figure 10. 3D function surface of failure time of CFRP confined coal columns

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图 11 未约束煤样不同高度处环向应变变化

Figure 11. Variation in hoop strain with different heights of unconfined coal specimens

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图 12 CFRP约束煤样不同高度处环向应变变化

Figure 12. Variation in hoop strain with different heights of CFRP-confined coal specimens

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图 13 CFRP布约束煤圆柱强度增强比-加载速率关系

Figure 13. Relationship between strength enhancement ratio and loading rate of CFRP confined coal columns

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图 14 CFRP布约束煤圆柱强度增强比三维函数曲面

Figure 14. 3D surface of strength enhancement ratio of CFRP confined coal columns

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图 15 CFRP约束煤圆柱体受力平衡关系

t_CFRP—CFRP thickness; f_CFRP—Tensile strength of CFRP; f_h—Hoop constraint force provided by CFRP

Figure 15. Force equilibrium relationship of CFRP confined coal columns

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图 16 CFRP布约束煤圆柱强度修正模型拟合结果

Figure 16. Fitting results of strength of CFRP confined coal columns by modified models

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图 17 CFRP布约束煤圆柱强度理论值与试验值对比

I_AE—Integral absolute error

Figure 17. Comparison of strength of CFRP confined coal columns between theoretical and experimental value

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表 1 碳纤维增强聚合物(CFRP) 加固煤圆柱的主要试验结果

Table 1. Main test results of coal columns strengthened with carbon fiber-reinforced polymer (CFRP)

Group	Specimen	D/mm	H/mm	v/(mm·min⁻¹)	n/layers	f_pu/MPa	f_pc/MPa	n_f	t_f/s
1	A-CC-1	49.60	100.19	0.01	0	15.79	—	—	2010.50
	A-CC-2	49.70	100.32	0.01	0	16.14	—	—	—
	A-CC-3	49.70	100.48	0.01	0	25.20	—	—	—
	A-1CFRP-CC-1	49.44	100.37	0.01	1	—	118.12	6.203	12360.45
	A-1CFRP-CC-2	49.62	100.52	0.01	1	—	123.28	6.474	—
	A-2CFRP-CC-1	49.63	100.40	0.01	2	—	207.08	10.874	29193.37
	A-2CFRP-CC-2	49.64	100.50	0.01	2	—	220.00	11.553	—
2	B-CC-1	49.59	100.37	0.1	0	19.03	—	—	259.73
	B-CC-2	49.84	100.44	0.1	0	27.52	—	—	—
	B-CC-3	49.68	100.28	0.1	0	26.29	—	—	—
	B-1CFRP-CC-1	49.67	100.42	0.1	1	—	133.90	5.515	1110.39
	B-1CFRP-CC-2	49.57	100.40	0.1	1	—	127.70	5.259	—
	B-2CFRP-CC-1	49.70	100.37	0.1	2	—	181.73	7.485	1852.65
	B-2CFRP-CC-2	49.40	100.32	0.1	2	—	200.86	8.273	—
3	C-CC-1	49.55	100.54	1.0	0	20.95	—	—	23.99
	C-CC-2	49.63	100.39	1.0	0	23.99	—	—	—
	C-CC-3	49.61	100.24	1.0	0	31.94	—	—	—
	C-1CFRP-CC-1	49.64	100.29	1.0	1	—	163.25	6.370	105.44
	C-1CFRP-CC-2	49.68	100.32	1.0	1	—	136.76	5.337	—
	C-2CFRP-CC-1	49.81	100.40	1.0	2	—	187.18	7.304	146.59
	C-2CFRP-CC-2	49.83	100.32	1.0	2	—	186.96	7.296	—
4	D-CC-1	49.42	100.36	10.0	0	30.81	—	—	2.98
	D-CC-2	49.86	100.38	10.0	0	34.81	—	—	—
	D-CC-3	49.55	100.39	10.0	0	32.07	—	—	—
	D-1CFRP-CC-1	49.62	100.33	10.0	1	—	121.35	3.727	7.88
	D-1CFRP-CC-2	49.64	100.47	10.0	1	—	110.40	3.390	—
	D-2CFRP-CC-1	49.89	100.37	10.0	2	—	189.72	5.826	12.36
	D-2CFRP-CC-2	49.74	100.51	10.0	2	—	222.41	6.830	—
Notes：In the specimen, A, B, C, D—Loading rates of 0.01, 0.1, 1.0 and 10 mm·min⁻¹, respectively; Number before CFRP—CFRP layer number; CC—Coal column; The last number—Specimen number with the same parameters. D—Diameter of coal; H—Height of coal; v—Loading rate; n—Number of CFRP layers; f_pu—Peak strength of unconfined coal columns; f_pc—Peak strength of CFRP-confined coal columns; n_f—Strength enhancement ratio of CFRP-confined coal columns; t_f—Average failure time.

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表 2 CFRP平均力学性能指标

Table 2. Average mechanical properties of CFRP sheets

Thickness/ (mm·ply⁻¹)	Tensile strength/MPa	Ultimate tensile strain/%	Elastic modulus/GPa
0.167	918.07	1.94	47.54

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表 3 代表性CFRP约束煤圆柱试样破坏

Table 3. Typical failure of CFRP confined coal column specimens

n/layer	Loading rate v/(mm·min⁻¹)
n/layer	0.01	0.1	1.0	10.0
0
1
2

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表 4 CFRP布约束煤圆柱强度修正模型参数

Table 4. Parameters of strength modified models of CFRP confined coal columns

Parameters	Modified Richart			Modified Hoek-Brown
Parameters	α	β	γ	Ψ	η	θ
Value	3.499	12.97	1.87	−1	292.77	0.22
R²	0.94			0.70
Note: α, β, γ, η, θ, Ψ—Undetermined parameter.

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