Several Analysis on Influence of Soft Ground to Piled Embankment Reinforced with Geosynthetics

International Research Journal of Advanced Engineering and Science ISSN: 2455-9024

Several Analysis on Influence of Soft Ground to Piled Embankment Reinforced with Geosynthetics Pham Anh Tuan University of Science and Technology-The University of Danang, Vietnam

Abstract— The main focus of this paper is to present influence of some crucial parameters such as embankment height, soft ground depth, elastic modulus of soft ground and tensile stiffness of geosynthetic to the interacting mechanisms of geosynthetic reinforced pile supported embankment (GRPS). From the analysis results in this study show the influence of pile-soil-geosynthetic interaction to distribution of strain-stress. In addition, the results about efficiency, stress concentration ratio, settlement ratio, tension and axial strain of geosynthetic are intended to provide an insight for designer, who are facing many difficulty and challenge in the design process.

were selected for the calibration of this numerical model. The details of this calibration can be found in the paper of Han et al. [6], therefore, a brief description of this calibration presented as below.

A. Numerical Model and Theoritical Analysis A 2D finite element method, incorporated in fast Lagrangian analysis continue (Plaxis) Version 8.5 [7]. was adopted in this study. The numerical model for calibration against this case study is presented in figure 1. Several important factors will be considered in this paper include efficiency, stress concentration ratio, settlement ratio, tension and axial strain of geosynthetic.

Where the "efficiency E" of the pile support is defined as the proportion of the embankment weight carried by the piles.

The stress concentration ratio n, which is defined as the ratio of the stress on the pile caps to the soil between the pile caps (n=σp/σs). The stress concentration ratio n is a global index which incorporates the mechanism of the soil arching, tension membrane or apparent cohesion effect and pile-soil stiffness difference. Settlement ratio that is defined as settlement of original soft ground to settlement of geosynthetic, s/s0, where s0= σsD/Ec. (Figure 2)

Keywords— Embankment, geosynthetic, arching effect, stress concentration ratio, settlement ratio.

I.

ĐẶT VẤN ĐỀ

Pile embankment are increasingly used to construct highways on soft soils due to their rapid construction, low costs, and small total and differential settlement compared to the traditional soft soil improvement methods such as preloading, vertical drains or grounting injection as Magan [1], Shen et.al [2], Ariema and Butler [3]. Geosynthetic reinforcement platform(GRP) has been successfully in corporated with pile foundation as an intergrated system to reduce settlements, minimize yield of the soil above the pile cap, and enhance the efficiency of load transfer (Han and Gabrs [4], Pham et al.,[5], Han and Collin [6], Vegar Mayer and Shao [7]). The integrated system combines vertical piles and horizontally placed geosynthetics to form a relatively stiff platform that transfer embankment load to a deep competent bearing layer.

The load from the embankment must be effectively transferred to the piles and to prevent punching of the piles through the embankment fill creating differential settlement at the surface of the embankment. If the piles are placed close enough together, soil arching will occur and the load will be transferred to the piles more effectively.

The scope of this paper is the analysis of geosynthetic reinforced pile supported embankments, installed through soft soil, with a commercially available finite element software and sopil model. And one aim of the paper will focus on studying influence of several factors such as embankment height, soft ground depth, soft ground elastic modulus, and geosynthetic tensile stiffness on efficiency, stress concentration ratio, settlement ratio, tension of geosynthetic, and axial strain of geosynthetic.

II.

Surchage load Geosynthetic Embankment

H

Soft soil

L

stratum layer

Fig. 1. Cross section of embankment.

Stress acting on top of geosythetic

T

T

Cap pile

Cap pile Reaction below the geosynthetic max = tEc/D at the middle point

Pile

Pile

s

b

CALIBRATION OF NUMERICAL MODEL

s'

b

Fig. 2. Idealized stress distribution on geosynthetic.

To ensure reasonableness of the numerical model to be used for the parameter study, a design method of Low.et al.

(1994) [8], method of Guido et al. [9], method of BS8006 [10]

B. Brief Project Description A piled embankment is analyzed using the new simple method. The influence of embankment height, soft ground 21

Pham Anh Tuan, “Several analysis on influence of soft ground to piled embankment reinforced with geosynthetics,” International Research Journal of Advanced Engineering and Science, Volume 1, Issue 3, pp. 21-27, 2016.

International Research Journal of Advanced Engineering and Science ISSN: 2455-9024

depth, soft ground elastic modulus, and geosynthetic tensile stiffness on efficiency, stress concentration ratio, settlement ratio, tension of geosynthetic, and axial strain of geosynthetic is investigated. The geometric of the embankment and design parameters used in the present case study obtained from Chen.et al. (2006). They are as follow: pile cap width = 1.13m, embankment fill-height = 4.52m (assumed), soft ground depth = 25m, Factor of λ =0.8 (assumed). A surcharge of 12kPa is used to simulate the traffic load. In this paper, these values are used throughout unless otherwise specified.

No partial factors of safety are applied to the design parameters. The results of present case study are shown in figure 5-24.

likely to approach a limiting value at a very large height. The stress concentration ratio for reinforced case is higher than that for unreinforced due to that the geosynthetic enhances the load transfer from the soft soil to the pile caps. For present case, geosynthetic increases stress concentration ratio by 35-280%.

100

Efficiency (%)

b/s'=1:2 b/s'=1:3

a

80 70 60 50

TABLE I. Comparison of results from theoretical method and numerical analysis.

Factor With Geosynthetic Numerical Low et Guido BS8006 method al. et al.

Settlement ratio(s/s0) 0.36 0.41 Vertical stress on pile 69.30 70.2 71.83 63.05 (kN/m2), σp Vertical stress on 15.81 14.49 34.68 20.90 geosynthetic (kN/m2) Tension in geosynthetic 39.18 34.0 44.4 30.55 (kN/m2) Efficiency (%), E 78.08 79.91 51.94 71.04 Stress concentration 4.38 4.89 2.07 3.02 ratio, n

40 1

2

3

4

5

6

H/s'

(a) 100

b/s'=1:1.5 b/s'=1:2.5

Efficiency (%)

90

b/s'=1:2 b/s'=1:3

b

80 70 60 50 40

In general, the results from numerical analysis obtained a good match with other methods. Especially, with method of Low.et al. This will be basis for widening to numerical analysis.

III.

b/s'=1:1.5 b/s'=1:2.5

90

1

2

3

H/s'

4

5

6

(b) Fig. 3. Effect of embankment height on efficiency (a-without geosyntheic, bwith geosynthetic).

ANALYSIS OF RESULTS Stress concentration ratio

A. The Influence of Embankment Height Figure 3 shows the influence of embankment fill height on efficiency at different ratio of the pile cap width with to the clear spacing. It can be seen that efficiency increases with increasing area ratio. It can also be seen that the efficiency for the unreinforced case increases with increasing embankment fill height, but it likely to approach a limiting value at a very large height, while that for the reinforced case decreases with increasing embankment fill height at small values of area ratio and increases with increasing embankment fill height at large values of area ratio. The efficiency for reinforced case is higher than that for unreinforced due to that the geosynthetic enhances the load transfer from the soft soil to the pile caps.

For the present case study, geosynthetic increases efficiency by 7-75%.

Figure 4 shows the influence of embankment fill height on stress concentration ratio at different ratio of the pile cap width with to the clear spacing. It can be seen that stress concentration ratio increases with increasing area ratio for both the unreinforced case and reinforced case. It can also be seen that the stress concentration ratio for the unreinforced case increases with increasing embankment fill height, but it is likely to approach a limiting value at a very large height, while that for the reinforced case increases with increasing embankment fill height at large values of area ratio, but it is

10 9 8 7 6 5 4

b/s'=1:1.5 b/s'=1:2.5

b/s'=1:2 b/s'=1:3

3 2 1

a 1

2

3

4

5

6

H/s'

Stress concentration ratio

(a) 10 9 8 7 6

b/s'=1:1.5 b/s'=1:2.5

b/s'=1:2 b/s'=1:3

5 4 3 2 1

b 1

2

3

4

5

6

H/s'

(b) Fig. 4. Effect of embankment height on stress concentration ratio (a-without geosyntheic, b-with geosynthetic)

22 Pham Anh Tuan, “Several analysis on influence of soft ground to piled embankment reinforced with geosynthetics,” International Research Journal of Advanced Engineering and Science, Volume 1, Issue 3, pp. 21-27, 2016.

International Research Journal of Advanced Engineering and Science ISSN: 2455-9024

Figure 5 shows the influence of embankment fill height on settlement ratio (settlement of original soft ground, s/s0, where s0= σsD/Ec) at different ratio of the pile cap width with to the clear spacing. It can be seen that settlement ratio decreases with increasing area ratio. It can also be seen that the settlement ratio decreases with increasing embankment fill height, but it is likely to approach a limiting value at a very large height.

Figure 6 shows the influence of embankment fill height on tension of geosynthetic at different ratios of the pile cap width to the clear spacing. It is clear that tension of geosynthetic decreases with increasing area ratio. It is also clear that tension of geosynthetic increases with increasing embankment fill height. Tension of geosynthetic become more obvious for small values of area ratio and large values of embankment fill height.

Figure 7 shows the influence of embankment fill height on axial strain of geosynthetic at different ratios of the pile cap width to the clear spacing. It is clear that axial strain of geosynthetic decreases with increasing area ratio. It is also clear that tension of geosynthetic increases with increasing embankment fill height. Axial strain of geosynthetic become more obvious for small values of area ratio and large values of embankment fill height.

0.1

b/s'=1:1.5 b/s'=1:2.5

Axial strain

0.08

b/s'=1:2 b/s'=1:3

0.06 0.04 0.02

0.6

0 b/s'=1:1.5 b/s'=1:2.5

Settlement ratio

0.5

b/s'=1:2 b/s'=1:3

5

0.4

10

15 20 Soft ground depth (m)

25

30

Fig. 8. Effect of soft ground depth on axial strain.

0.3

B. The Influence of Soft Ground Depth Figure 8 shows the influence of soft ground depth on axial strain of geosynthetic at different ratios of the pile cap width to the clear spacing. It is clear that axial strain of geosynthetic decreases with increasing area ratio. In addition, tension of geosynthetic increases with increasing soft ground depth.

0.2 0.1 0 1

2

3

4

5

6

H/s'

Fig. 5. Effect of embankment height on settlement ratio.

100 b/s'=1:1.5 b/s'=1:2.5

400

b/s'=1:1.5 b/s'=1:2.5

90

b/s'=1:2 b/s'=1:3

Efficiency (%)

Tension (kN/m)

500

300 200

b/s'=1:2 b/s'=1:3

a

80 70 60 50

100

40 5

0 1

2

3

4

5

10

6

H/s'

15 20 Soft ground depth (m)

25

30

(a)

Fig. 6. Effect of embankment height on tension.

100

b 0.2

b/s'=1:1.5 b/s'=1:2.5

Axial Strain

0.16

Efficiency (%)

90 b/s'=1:2 b/s'=1:3

0.12

80 70 60 50

0.08

b/s'=1:1.5 b/s'=1:2.5

40

0.04

5

0 1

2

3

4

5

10

b/s'=1:2 b/s'=1:3

15 20 Soft ground depth (m)

25

30

(b) Fig. 9. Effect of soft ground depth on efficiency (a-without geosyntheic, bwith geosynthetic).

6

H/s'

Fig. 7. Effect of embankment height on axial strain.

23 Pham Anh Tuan, “Several analysis on influence of soft ground to piled embankment reinforced with geosynthetics,” International Research Journal of Advanced Engineering and Science, Volume 1, Issue 3, pp. 21-27, 2016.

International Research Journal of Advanced Engineering and Science ISSN: 2455-9024

b/s'=1:1.5 b/s'=1:2.5

8

b/s'=1:2 b/s'=1:3

Settlement ratio

b/s'=1:2 b/s'=1:3

0.6 0.4 0.2

5

10

15 20 Soft ground depth (m)

25

30

Fig. 11. Effect of soft ground depth on settlement ratio.

160

b/s'=1:1.5 b/s'=1:2.5

140

a

b/s'=1:2 b/s'=1:3

120 100 80 60 40 20

6

5

10

15 20 Soft ground depth (m)

4

25

30

Fig. 12. Effect of soft ground depth on tension.

2 100

0 5

10

15 20 Soft ground depth (m)

25

90

30

(a) 70

b/s'=1:1.5 b/s'=1:2.5

60

b/s'=1:2 b/s'=1:3

b

b/s'=1:1.5 b/s'=1:2.5

b/s'=1:2 b/s'=1:3

a

80 70 60 50

50

40 2000

40 30

2500

3000

3500

4000

4500

Elastic modulus (kN/m2)

20

(a)

10

100

0 5

10

15 20 Soft ground depth (m)

25

30

Efficiency (%)

Stress concentration ratio

b/s'=1:1.5 b/s'=1:2.5

0.8

0

Tension (kN/m)

10

1

Efficiency (%)

Stress concentration ration

Figure 9 shows the influence of soft ground depth on efficiency at different ratio of the pile cap width with to the clear spacing. It can be seen that efficiency increases with increasing area ratio. As the same time, the efficiency decreases with increasing soft ground depth. The efficiency for reinforced case is higher than that for unreinforced case due to that the geosynthetic enhances the load transfer from the soft soil to the pile caps.

Figure 10 shows the influence of soft ground depth on stress concentration ratio at different ratio of the pile ca at different ratio of the pile cap width with to the clear spacing. It can be seen that stress concentration ratio decreases with increasing area ratio. It can also be seen that the stress concentration ratio decreases with increasing soft ground depth. The stress concentration ratio for reinforced case is higher than that for unreinforced case due to that the geosynthetic enhances the load transfer from the soft soil to the pile caps.

(b) Fig. 10. Effect of soft ground depth on stress concentration ratio (a-without geosyntheic, b-with geosynthetic).

90

b/s'=1:1.5 b/s'=1:2.5

b/s'=1:2 b/s'=1:3

b

80 70 60

Figure 11 shows the influence of soft ground depth on settlement ratio at different ratio of the pile cap width with to the clear spacing. It can be seen that settlement ratio decreases with increasing area ratio. It can also be seen that the settlement ratio decreases with increasing soft ground depth.

Figure 12 shows the influence of soft ground depth on tension of geosynthetic at different ratios of the pile cap width to the clear spacing. It is clear that tension of geosynthetic decreases with increasing area ratio. In addition, tension of geosynthetic increases with increasing soft ground depth.

50 2000

2500

3000

3500

4000

4500

Elastic modulus (kN/m2)

(b) Fig. 13. Effect of soft ground elastic modulus on efficiency (a-without geosyntheic, b-with geosynthetic).

C. The Influence of Soft Ground Elastic Modulus Figure 13 shows the influence of soft ground elastic modulus on efficiency at different ratio of the pile cap width with to the clear spacing. It can be seen that efficiency 24

Pham Anh Tuan, “Several analysis on influence of soft ground to piled embankment reinforced with geosynthetics,� International Research Journal of Advanced Engineering and Science, Volume 1, Issue 3, pp. 21-27, 2016.

International Research Journal of Advanced Engineering and Science ISSN: 2455-9024

Stress concentration ratio

increases with increasing area ratio. It can also be seen that the efficiency increases with increasing soft ground elastic modulus. The efficiency for reinforced case is higher than that for unreinforced case due to that the geosynthetic enhances the load transfer from the soft soil to the pile caps.

Figure 14 shows the influence of soft ground elastic modulus on stress concentration ratio at different ratio of the pile ca at different ratio of the pile cap width with to the clear spacing. It can be seen that stress concentration ratio decreases with increasing area ratio. It can also be seen that the stress concentration ratio increases with increasing soft ground elastic modulus. The stress concentration ratio for reinforced case is higher than that for unreinforced case due to that the geosynthetic enhances the load transfer from the soft soil to the pile caps.

Figure 15 shows the influence of soft ground elastic modulus on settlement ratio at different ratio of the pile cap width with to the clear spacing. It can be seen that settlement ratio decreases with increasing area ratio. It can also be seen that the settlement ratio increases with increasing soft ground elastic modulus.

160

b/s'=1:1.5 b/s'=1:2.5

Tension (kN/m)

140 120 100 80 60 40 20 2000

20

b/s'=1:1.5 b/s'=1:2.5

b/s'=1:2 b/s'=1:3

b/s'=1:2 b/s'=1:3

2500

a

3000

3500

4000

4500

Elastic modulus (kN/m2)

15

Fig. 16. Effect of ground elastic modulus on tension.

10

Figure 16 shows the influence of soft ground elastic modulus on tension of geosynthetic at different ratios of the pile cap width to the clear spacing. It is clear that tension of geosynthetic decreases with increasing area ratio. In addition, tension of geosynthetic decreases with increasing soft ground elastic modulus.

5 0 2000

2500

3000

3500

4000

4500

Elastic modulus (kN/m2)

b/s'=1:1.5 b/s'=1:2.5

0.1

b/s'=1:2 b/s'=1:3

b/s'=1:1.5 b/s'=1:2.5

0.08 Axial strain

Stress concentration ratio

(a) 20 15 10

0.06 0.04 0.02

5

b 0 2000

2500

3000

3500

4000

0 2000

2500

4500

3000

0.1

b/s'=1:1.5 b/s'=1:2.5

0.8

Axial strain

0.08 b/s'=1:1.5 b/s'=1:2.5

4000

4500

Fig. 17. Effect of elastic modulus on axial strain.

(b) Fig. 14. Effect of ground elastic modulus on stress concentration ratio(awithout geosyntheic,b-with geosynthetic).

1

3500

Elastic modulus (kN/m2)

Elastic modulus (kN/m2)

Settlement ratio

b/s'=1:2 b/s'=1:3

b/s'=1:2 b/s'=1:3

0.6

b/s'=1:2 b/s'=1:3

0.06 0.04 0.02

0.4 0 500

0.2 0 2000

1000

1500

2000

2500

3000

Geosynthetic tensile stiffness (kN/m2)

2500

3000

3500

4000

Fig. 18. Effect of geo tensile stiffness on axial strain.

4500

Elastic modulus (kN/m2)

Figure 17 shows the influence of soft ground elastic modulus on axial strain of geosynthetic at different ratios of the pile cap width to the clear spacing. It is clear that axial

Fig. 15. Effect of elastic modulus on settlement ratio.

25 Pham Anh Tuan, “Several analysis on influence of soft ground to piled embankment reinforced with geosynthetics,� International Research Journal of Advanced Engineering and Science, Volume 1, Issue 3, pp. 21-27, 2016.

International Research Journal of Advanced Engineering and Science ISSN: 2455-9024

strain of geosynthetic decreases with increasing area ratio. It is also clear that tension of geosynthetic decreases with increasing soft ground elastic modulus.

unreinforced case due to that the geosynthetic enhances the load transfer from the soft soil to the pile caps.

b/s'=1:1.5 b/s'=1:2.5

Efficiency (%)

90

b/s'=1:2 b/s'=1:3

100

b/s'=1:1.5 b/s'=1:2.5

90

a

80 70 60 50 40 500

1000

1500

2000

2500

3000

(a)

a

80 70

100

b/s'=1:1.5 b/s'=1:2.5

90

b/s'=1:2 b/s'=1:3

b

80 70 60 50 40 500

60

1000

1500

2000

2500

3000

Geosynthetic tensile stiffness (kN/m2)

50 40 500

b/s'=1:2 b/s'=1:3

Geosynthetic tensile stiffness (kN/m2)

Stress concentration ratio

100

Stress concentration ratio

D. The Influence of Geosynthetic Tensile Stiffness Figure 18 shows the influence of geosynthetic tensile stiffness on axial strain of geosynthetic at different ratios of the pile cap width to the clear spacing. It is clear that axial strain of geosynthetic decreases with increasing area ratio. It is also clear that tension of geosynthetic decreases with increasing geosynthetic tensile stiffness.

Figure 19 shows the influence of geosynthetic tensile stiffness on efficiency at different ratio of the pile cap width with to the clear spacing. It can be seen that efficiency increases with increasing area ratio. It can also be seen that the efficiency decreases gradually with increasing geosynthetic tensile stiffness. The efficiency for reinforced case is higher than that for unreinforced case due to that the geosynthetic enhances the load transfer from the soft soil to the pile caps.

1000

1500

2000

2500

(b) Fig. 20. Effect of geos. tensile stiffness on stress concentration ratio(a-without geosyntheic, b-with geosynthetic).

3000

Geosynthetic tensile stiffness (kN/m2) 1

b/s'=1:1.5 b/s'=1:2.5

100

b/s'=1:1.5 b/s'=1:2.5

Efficiency (%)

90

b/s'=1:2 b/s'=1:3

Settlement ratio

(a) b

80 70

0.8

b/s'=1:2 b/s'=1:3

0.6 0.4 0.2

60

0 500

50 40 500

1000

1500

2000

2500

3000

Geosynthetic tensile stiffness (kN/m2) 1000

1500

2000

2500

3000

Fig. 21. Effect of geo. tensile stiffness on settlement ratio.

Geosynthetic tensile stiffness (kN/m2)

(b) Fig. 19. Effect of geosynthetic tensile stiffness on efficiency (a-without geosyntheic, b-with geosynthetic).

180

b/s'=1:1.5 b/s'=1:2.5

160

b/s'=1:2 b/s'=1:3

140

Tension

Figure 20 shows the influence of geosynthetic tensile stiffness on stress concentration ratio at different ratio of the pile ca at different ratio of the pile cap width with to the clear spacing. It can be seen that stress concentration ratio decreases with increasing area ratio. It can also be seen that the stress concentration ratio decreases with increasing geosynthetic tensile stiffness, but it is likely to approach a limiting value at a very large geosynthetic tensile stiffness. The stress concentration ratio for reinforced case is higher than that for

120 100 80 60 40 20 500

1000

1500

2000

2500

3000

Geosynthetic tensile stiffness (kN/m2)

Fig. 22. Effect of geo. tensile stiffness on tension.

26 Pham Anh Tuan, “Several analysis on influence of soft ground to piled embankment reinforced with geosynthetics,� International Research Journal of Advanced Engineering and Science, Volume 1, Issue 3, pp. 21-27, 2016.

International Research Journal of Advanced Engineering and Science ISSN: 2455-9024

Figure 21 shows the influence of geosynthetic tensile stiffness on settlement ratio at different ratio of the pile cap width with to the clear spacing. It can be seen that settlement ratio decreases with increasing area ratio. It can also be seen that the settlement ratio decreases with increasing geosynthetic tensile stiffness.

Figure 22 shows the influence of geosynthetic tensile stiffness on tension of geosynthetic at different ratios of the pile cap width to the clear spacing. It is clear that tension of geosynthetic decreases with increasing area ratio. It is also clear that tension of geosynthetic increases with increasing geosynthetic tensile stiffness.

As a result the net stress acting on the geotextile increases with the soft ground depth and geosynthetic tensile stiffness, and increases with the embankment height and soft ground elastic modulus.

REFERENCES S. W. Abusharar, J.-J. Zheng, B.-G. Chen, and J.-H. Yin, “A simplified method for analysis of a piled embankment,” Geotextiles and Geomembranes, vol. 27, issue 1, pp. 39–52, 2009.

[2] R. P. Chen, Y. M. Chen, and Z. Z. Xu, “Interaction of rigid pilesupported embankment on soft soil,” ASCE Geotechnical Special Publication, vol. 131, pp. 231–238, 2006.

[3] F. Ariema and B. E. Butler, “Embankment Foundations – Guide to Earthwork Construction,” Transportation Research Board, National Research Council, Washington, D.C., pp. 59–73, 1990.

[4] J. Han and M. Gabr, “Numerical analysis of geosynthetic reinforced and pile-supported,” Journal of Geotechnical, vol. 128, issue 1, pp. 44-53, 2001.

[5] H. T. V. Pham, M. T. Suleiman, and D. J. White, “Numerical analysis of geosyntheticrammed aggregate pier-supported embankment,” in Proceedings of Geotrans Conference, ASCE Geotechnical Special Publication, vol. 126, pp. 657–664. 2004.

[6] J. Han and J. G. Collin, “Geosynthetic support system over pile foundations,” in Geotechnical Special Publication, 130–142, pp. 3949– 3953, 2005.

[7] P. J. Naughton and G. T. Kempton, “Comparison of analytical and numerical analysis design methods for piled embankments,” in Proceedings of the Geo- Frontiers, ASCE Geo-Institute and IFAI Geosynthetic Institute, Austin, TX, pp. 135–144, 2005.

[8] B. K. Low, S. K. Tang, and V. Choa, “Arching in piled embankments,” Journal of Geotechnical Engineering, vol. 120, issue 11, pp. 1917–1938, 1994.

[9] V. A. Guido, J. D. Kneuppel, and M. A. Sweeny, “Plate loading tests on geogridreinforced earth slabs,” in Proceedings of the Geosynthetics ’87, New Orleans, USA, IFAI, pp. 216–225, 1987.

[10] BS (British Standards Institution), “Code of practice for strengthened/reinforced soils and other fills,” British Standards Institution, London, pp. 198, 1995.

[1]

E. Comment The working stress of the geotexile depends on complex interaction of fill properties, soft groiund properties, and geotexile properties.

The geosynthetic is more effective when soft soil is very compressible, because the axial force in the geosynthetic increases with increasing the settlement of soft ground.

The settlement decreases with increasing the soft ground elastic modulus and geosynthetic tensile stiffness, and increases with increasing the embankment fill height and soft soil depth as expected. The fill load carried by piles decreases with increasing the soft ground depth and geosynthetic tensile stiffness, and increases with increasing the embankment height and soft ground elastic modulus, because the reaction of soft ground on geosynthetic decreases with increasing the soft ground depth and geosynthetic tensile stiffness, and increases with increasing the embankment height and soft ground elastic modulus.

27 Pham Anh Tuan, “Several analysis on influence of soft ground to piled embankment reinforced with geosynthetics,” International Research Journal of Advanced Engineering and Science, Volume 1, Issue 3, pp. 21-27, 2016.