1

APPLICATION OF GEO-SYNTHETIC MATERIALS IN GEOTECHNICAL ENGINEERING Faculty: Samirsinh .P.ParmarDepartment of Civil EngineeringFaculty of Technology, Dharmasinh Desai University,NadiadMail Add: samirddu@gmail.com

2

RETAINING WALLS

Schematic diagram of a geosynthetic-reinforced soil retaining wall.

Function Of Geosynthetic is :To reinforce, retain, and protect backfill/soil for improving stability

3

COMPONENTS OF GEOSYNTHETIC-REINFORCED RETAINING WALL A geosynthetic-reinforced retaining wall has

thus three basic components:1. Backfill, which is usually specified to be

granular soil;2. Reinforcement layers, which are generally

geotextile or geogrid layers;3. Facing element, which is not necessary but

usually used to maintain appearance and to avoid soil erosion between the reinforcement layers.

4

COMPONENT OF E.R. WALL

5

Reinforcing Strips

Facing Elements

6Side views of geosynthetic-reinforced retaining walls: (a) with wraparound geosynthetic facing; (b) with gabion facing; (c) with full-height precast concrete panel facing; (d) with segmental or MCBs facing.

7

EMBANKMENTS

Embankment over weak foundation soils: (a) embankment on uniform weak foundation soil; (b) embankment on locally weak foundation soil with lenses of clay or peat, or with sinkholes (after Bonaparte and Christopher, 1987).

8Embankment over weak foundation soil: (a) with basal drainage layer; (b) with vertical drains and basal drainage layer.

Functions of GT: To keep embankment materials separated from soft foundation soil Separation from not being changed in behaviour over the service period . To improve stability of embankment edges, to bridge soft foundation Reinforcement soils, to make steep-sided slopes

9

SHALLOW FOUNDATIONS

Reinforced foundation soils supporting footings of structures.

Functions of GT:• To improve load-bearing capacity, to reduce settlement.• To prevent erosion and scouring around underwater foundations using Containment, screening bags, tubes, and mattresses filled with soil,• To form underwater foundations

10

ROADS

Functions of GT:To prevent/control water infiltration Fluid barrierTo prevent/control reflective cracking

11

12

CONCEPT OF GEOSYNTHETIC SEPARATION IN PAVED ROADWAYS

13

EFFECT OF CYCLIC LOAD ON GT

14

GEOTEXTILE FOR EMBANKMENT CONSTRUCTION

Concept of membrane-encapsulated soil layer (MESL) as a base/sub base course in paved roadways.

15

RAILWAY TRACKS

To prevent ballast contamination Separation To dispose of water to side drains Filtration, drainage To prevent contamination in railroad refuelling areas,

to prevent Fluid barrier, protection upward groundwater movement in a railroad cut

To reinforce track systems and distribute loads.

Functions of GT:

16

Principal functions when a properly designed geosynthetic is installed within the track structure. Separation, in new railway tracks, between soil subgrade and new

ballast; Filtration of soil pore water rising from the soil subgrade beneath the

geosynthetic, due to rising water conditions or the dynamic pumping action of the wheel loadings, across the plane of the geosynthetic;

Lateral confinement-type reinforcement in order to contain the overlying ballast stone;

Lateral drainage of water entering from above or below the geosynthetic within its plane leading to side drainage ditches.

17

FILTERS AND DRAINS

(a) A use of geotextile filter; (b) a use of drainage geocomposite.

18

FILTER LAYERS USING GEOTEXTILE.

19

COMPARISON OF GRANULAR AND GEOTEXTILE FILTERS (MODIFIED FROM PILARCZYK, 2000)

20

Schematic views of (a) blocking; (b) blinding; (c) clogging mechanisms

(a) (b)

(c) In filter applications, the design must be prepared so as to avoid, throughout the design life, the following three phenomena causing decrease of the permeability of the geotextile filter in course of time:1. Blocking2. Blinding3. Clogging

21

SLOPE EROSION PROTECTION

(a) conventional revetment system consisting wholly of granular Materials.(b) revetment system containing a geotextile filter.

22

Geogrid with soil nailing.

Erosion control using geosynthetic mat and geotextile along with vegetation.

23

STABILIZATION

Role of reinforcement in slopes: (a) increase factor of safety.(b) stabilize steepened portion of slope (after Simac, 1992).

24

REINFORCEMENT ORIENTATIONS: (A) IDEALIZED(B) PRACTICAL (AFTER INGOLD, 1982A).

Functions of GT: To protect soil slope against erosion along with slope

armour Filtration To protect earthen slopes against erosion while

vegetation is being Vegetative reinforcement, established surface stabilization

To prevent erosion and scouring using bags, tubes, and mattresses Containment, screening filled with soil

To prevent soil slope against movement/sliding

25

GEOMETRIC PARAMETERS FOR A SURFACE STRIP FOUNDATION ON GEOGRID-REINFORCED CLAY SLOPE(AFTER DAS ET AL., 1996).

26

CONTAINMENT FACILITIES: LANDFILL

Types of solid waste landfill geometry: (a) area fill; (b) trench fill; (c) above and below ground fill; (d) valley fill (after Repetto, 1995).

27

CONTAINMENT FACILITIES: LANDFILL

Geosynthetic Clay Liner (GCL)

Functions of GT: To prevent leachate from infiltrating into soil Fluid barrier, protectionTo drain leachate

28

29

PONDS, RESERVOIRS, AND CANALS

Typical cross-sections: (a) liquid pond/reservoir; (b) canal.

30

EARTH DAMS

Functions of GT: To reduce seepage through the dam.

embankment, to provide Fluid barrier, protection upstream face infiltration cut-off

To prevent internal erosion/piping Filtration, protection

To drain seepage water.

31

TUNNELS

Functions of GT: To prevent seepage To provide drainage

of seepage water

32

QUESTION S??