Effect of Different Fibers on Soil Mechanical Properties and Mechanism Analysis

doi:10.11988/ckyyb.20230507

Abstract

Abstract:

To investigate how different fibers influence soil reinforcement, basalt fiber and glass fiber were separately added to the same soil. Unconfined compressive strength tests were performed to compare the stress-strain curves and analyze the relationship between strength and both fiber content and fiber length for the two types of fiber-reinforced soil. Additionally,fiber anchorage test was conducted to explore the mechanisms of fibers enhancing soil strength. The results demonstrate that fiber-reinforced soil exhibits significantly greater compressive strength compared to plain soil. As fiber length increases, the strength of both basalt and glass fiber-reinforced soils first rises and then falls, with the optimal fiber length being 9 mm. Similarly, increasing fiber content causes the strength of both types of fiber-reinforced soil to fluctuate, with two peaks observed; the optimal fiber content is 0.5%. The fiber anchorage tests reveal that the pull-out force of the fibers varies with changes in fiber spacing. At small spacings, fibers interact, resulting in peak and valley values of pull-out force. As fiber spacing increases and reaches a critical anchorage distance, fibers no longer affect each other.

Key words: basalt fibre, glass fibre, fiber-reinforced soil, unconfined compressive strength, fiber anchorage

CLC Number:

TU411.6土的抗压强度试验

NIU Lei, WU Zhan-jun, XU Li-na, BI Su-hong, HUANG Zhan-fang. Effect of Different Fibers on Soil Mechanical Properties and Mechanism Analysis[J]. Journal of Yangtze River Scientific Research Institute, 2024, 41(11): 144-150.

Figures/Tables 16

Table 1 Physical and mechanical parameters of fibers

纤维类型	单丝直径/μm	抗拉强度/MPa	弹性模量/GPa
玄武岩纤维	13	2 611	85.9
玻璃纤维	11	1 240	75.0

Fig.1 Appearances of fibers

Fig.2 Curves of dry density versus moisture content

Table 2 Parameters of two groups of samples

纤维长度/mm	不同纤维掺量下试验编号
纤维长度/mm	0.1%	0.3%	0.5%	0.7%
3	B1	B2	B3	B4
6	C1	C2	C3	C4
9	D1	D2	D3	D4
12	E1	E2	E3	E4

Fig.3 Static pressing device and loading device

Fig.4 Unconfined compressive strength versus fiber content of fiber-reinforced soil with varied fiber length

Fig.5 Failure of fiber-reinforced soil

Table 3 Strength growth rate of basalt fiber and glass fiber reinforced soils over plain soil

纤维类型	纤维长度/ mm	不同纤维掺量的加筋土较素土的强度增长率/%
纤维类型	纤维长度/ mm	0.1%	0.3%	0.5%	0.7%
玄武岩纤维	3	24.45	4.01	44.88	9.62
	6	56.31	22.24	66.33	26.26
	9	80.36	58.12	85.37	65.33
	12	24.65	5.20	28.46	4.21
玻璃纤维	3	17.84	13.83	44.09	31.03
	6	50.30	22.24	60.92	41.08
	9	79.96	58.12	83.77	78.96
	12	14.23	5.20	19.44	13.23

Fig.6 Unconfined compressive strength of different fibers with varied length

Fig.7 Stress-strain curves of basalt fiber reinforced soil

Fig.8 Stress-strain curves of glass fiber reinforced soil

Fig.9 Forces acting on fiber

Fig.10 Compressive strengths of different fibers with varied length at fiber content 0.5%

Fig.11 Compressive strengths of different fibers with varied content at a length of 9 mm

Fig.12 Relationship between pull-out force and spacing

Fig.13 Change in the strength of 9 mm basalt fiber

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