Effects of fibre inclusion on sand failure Effects of fibre inclusion on 𝜀𝑎-q relationshipIntroduction

Using of fibres as the main

technique to reinforce soil has been

widely used in construction

especially in consolidated

foundation. As a result, a great

numbers of researchers focus on

exploring the mechanics behavior of

soil with adding fibers

reinforcement (Pino & Baudet,

2015). However, most of the

researches have devoted to find the

advantages of fiber inclusion on

increasing soil’s shearing strength.

Few studies have focused on the

effect of particle size on fibre-

reinforcement. Therefore, this study

will investigate the mechanical

behavior of two fibre-reinforced

sands with different particle sizes. A

series of drained triaxial

compression tests have been carried

out. The fibre content is 0.25%

(weight fraction) for all the samples.

• Pino, L. F. M., & Baudet, B. A. (2015). The effect of the particle size distribution on the mechanics of fibre-reinforced sands under one-dimensional compression. Geotextiles and Geomembranes, 43(3), 250-258.

• Head, K.H (1982). Manual of Soil Laboratory testing. 2nd ed. London: Plymouth: Pentech Press. 335-743.

Effect of particle shape on mechanical behavior of fibre-reinforced sandStudent Name: Weifei Sheng (2110827) Tutor: Dr. Zhiwei Gao

Figure 1: Failure curves for pure sand and fibre-reinforced sand

with fine particles in the p-q plane.

Figure 2: Failure curves for pure sand and fibre-reinforced sand

with coarse particles in the p-q plane.

• Fiber inclusion can increase the shear strength of both

fine and coarse sand.

• The failure lines for pure sand and fibre-reinforced sand

with fine particles are almost parallel.

Figure 3: Relationship between axial strain (𝜀𝑎) and deviator stress (q) for fine sand specimen.

Figure 4: Relationship between axial strain (𝜀𝑎) and deviator stress (q) for coarse sand specimen.

Fibre inclusion can

• Increase the shear strength of sand (q at failure is higher

for fibre-reinforced sand).

• Increase the axial strain at failure

• Reduce the amount of strain softening

Effects of fibre inclusion on 𝜀𝑣 − 𝜀𝑎 relationship

Figure 5: Relationship between volumetric strain (𝜀v) and axial strain (𝜀𝑎) for fine sand specimen.

Figure 6: Relationship between volumetric strain (𝜀v) and axial strain (𝜀𝑎) for coarse sand specimen.

Fibre inclusion can

• Increase the amount of volumetric expansion for both of

the fine sands and coarse sands.

Effects of fibre inclusion on sands failure mode

Figure 7 (d)Figure 7 (a) Figure 7 (b) Figure 7 (c)

Figure 7 (a) to (d) represent the sands failure modes for fine sand without

fibres, fine sand with fibres, coarse sand without fibres and coarse sand

with fibres. Fibre inclusion can change the sands failure mode from brittle

failure to plastic failure (Head, 1982), and this effect is more obvious in

coarse sands.

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