**1. Introduction**

Landslides in slopes and failures of embankment and cut slopes lead to loss of life and property. Several factors, natural and manmade, such as heavy rainfall, unplanned construction, deforestation, restricting waterways of rivers and their tributaries are major causes for instability of slopes. Factors controlling stability of natural slopes are type of soil, environmental conditions, groundwater, stress history, rainfall, cloud burst, earthquakes, etc. Landslide mortality rate exceeds one per 100 km2 per year in developing countries like India, China, Nepal, Peru, Venezuela, Philippines and Tajikistan [1, 2]. Factors that cause man-made slope failure are very different and could be due to inadequate design, improper backfill, poor construction, etc. The repair of failed slope involves removal of debris and reinstatement of slope with free draining material. Restoration of the slide with geosynthetics can be simpler, faster and economical. Designing slopes with Geosynthetics has several advantages (Simac [3]), e.g., reduced land requirement, additional usable area at toe of slope, use of available on-site soil, reduced transportation costs of select fill or export costs of unsuitable fill, steeper slopes, elimination of concrete facing, and facilitation of natural vegetation for sustainable development.

**12**

*Slope Engineering*

**References**

LIEGE, p 149-162.

[1] LombardiG : La révision dans la construction des tunnels. Géologie et mécanique des roches,: COLLOQUE GEOLOGIE DE L'INGENIEUR; 1974 the SoilMechanics and Foundations Division, ASCE, SM1, 71-94. 1967.

[11] Pietro L: Fibre-Glass tubes to stabilize the face of tunnels in difficult

cohesive soils Seminar on "The application of fibre reinforced plastics (FRP) in civil structural engineering"

[12] Zienkiewicz O C, Taylor R L : La méthode des éléments finis : formulation de base et problèmes linéaires, AFNOR

[13] Pietro L: Design and construction of tunnels. editors. Springer-Verlag Berlin Heidelberg. p. 23-587. 2008. DOI:

[14] T.Baumann R,SternathJ, Schwarz : Face support for tunnels in losse grouds in ; world tunnel congress, tunnel for

[15] Huang M S,Jia C Q: Stability analysis of soil slopes subjected to unsaturated transient seepage, chinese journal of geotecnical engineering 28(2), 202-

éléments finis, 2éme Edition MALOINE

éléments finis, 2éme Edition MALOINE

[18] SABONNIERE J C, COULOMB J.C : Eléments finis et CAO, Edition

technique, Paris. 610-625.1991.

10.1007/978-3-540-73875-6.ch2

people 317-324;1997; Vienna.

[16] DHATT G., TOUZOT G Présentation de la méthode des

[17] DHATT G., TOUZOT G : Présentation de la méthode des

HERMES Paris, 210p.1986.

206, 2006.

Paris.1984.

Paris.1984.

Bolgne, 107-165.1993.

[2] Laca E, PanetM: Application du calcul à la rupture à la stabilité du front de taille d'un tunnel, Revue française de

préconfinement, Conférence Tenuta

[4] Pietro L: Design and Construction of Tunnels, Analysis of Controlled Deformation in Rocks and Soils. Springer-Verlag Berlin Heidelberg,

[5] TrompilleV: Etude expérimentale et théorique du comportement d'un tunnel renforcé par boulonnage frontal, Thèse de doctorat, INSA de Lyon,

[6] Chern JC, Shiao FY, Yu C.W:An empiricalsafetycriterion for tunnel construction: Proceedings of the Regional Symposium on Sedimentary Rock Engineering. Taipei, 222-227. 1998.

[7] Centre d'études des tunnels, Juillet. Dossier pilote des tunnels. France,

[8] Broere W: Tunnel Face Stability and New CPT Applications. Ph.D Thesis – Technical University of Delft,

[9] Davis E H, Gunn M J, Mair RJ, and Seneviratne H N: The stability of shallow tunnels and underground openings in cohesive material. Géotechnique, 30(4):397-416, 1980.

[10] Broms B, Bennermark H: Stability of clay at vertical openings', Journal of

géotechnique, n° 43, 5-20.1988.

[3] Pietro L : convergenceconfinement ou extrusion-

(Parigi),129-145.1998.

3-45. 2008.

19-20.2003.

21-27. 1998.

5-30. 2001.

**Figure 1.**

*Effect of geosynthetic reinforcement on geometry of embankment: (a) flat and (b) steep slopes.*

Embankments are built with engineered fills. Geosynthetics facilitate reduction of earthwork volume by altering the geometry of the embankment (**Figure 1**) and even allow use of marginal soil.

In reinforced soil, conventionally free draining material is specified for backfill due to its high strength and draining properties. The cost of fill material is about 40% of the total cost of the structure [4]. If marginal soil is used instead it could be more economical. Apart from economics, technical factors like esthetics, reliability, simple construction techniques, good seismic performance and ability to tolerate large deformations without structural distress have enhanced the acceptance and use of geosynthetics as reinforcing material.
