Geonet properties and test methods Notes | EduRev

: Geonet properties and test methods Notes | EduRev

 Page 1


Objectives_template
 Module 10:Design methods of Geogrids, Geonets and geomembranes 
 Lecture 29:Geonet properties and test methods 
 
 
The Lecture Contains: 
Applications
 
 
 
 
 
 
 
 
file:///D|/Dr.patra/ground_improvement_techniques/lecture29/29_1.htm [10/12/2011 11:56:31 AM]
Page 2


Objectives_template
 Module 10:Design methods of Geogrids, Geonets and geomembranes 
 Lecture 29:Geonet properties and test methods 
 
 
The Lecture Contains: 
Applications
 
 
 
 
 
 
 
 
file:///D|/Dr.patra/ground_improvement_techniques/lecture29/29_1.htm [10/12/2011 11:56:31 AM]
Objectives_template
 Module 10:Design methods of Geogrids, Geonets and geomembranes 
 Lecture 29:Geonet properties and test methods 
 
GEONETS
Formed by a continuous extrusion process into a net like configuration of intersecting ribs 
Figure 29.1
?     Geonets consisting of extruded solid ribs.                                         
?     Consisting of extruded solid ribs hence greater flow rate.
?     Made from drawn solid ribs, which allows for vertical rib intersections to be perpendicular, hence 
higher normal pressure.
Geonet properties and Test Methods:
Physical properties – Thickness, mass per unit area        
Mechanical properties: 
1.  Tensile strength :
Greater tensile strength in m/c direction.
    2. Compressive strength :
The solid extruded ribs perform much more uniformly but carry slightly less load as compared to foamed 
ribs at a given deformation. This is due to lower mass per unit area.
Types of Geonets Thickness
Solid rib extruder
  
5.6mm 
1060
Foamed rib extruder 7.9mm 1700
 
 
 
 
 
 
 
 
 
 
file:///D|/Dr.patra/ground_improvement_techniques/lecture29/29_2.htm (1 of 2) [10/12/2011 11:56:31 AM]
Page 3


Objectives_template
 Module 10:Design methods of Geogrids, Geonets and geomembranes 
 Lecture 29:Geonet properties and test methods 
 
 
The Lecture Contains: 
Applications
 
 
 
 
 
 
 
 
file:///D|/Dr.patra/ground_improvement_techniques/lecture29/29_1.htm [10/12/2011 11:56:31 AM]
Objectives_template
 Module 10:Design methods of Geogrids, Geonets and geomembranes 
 Lecture 29:Geonet properties and test methods 
 
GEONETS
Formed by a continuous extrusion process into a net like configuration of intersecting ribs 
Figure 29.1
?     Geonets consisting of extruded solid ribs.                                         
?     Consisting of extruded solid ribs hence greater flow rate.
?     Made from drawn solid ribs, which allows for vertical rib intersections to be perpendicular, hence 
higher normal pressure.
Geonet properties and Test Methods:
Physical properties – Thickness, mass per unit area        
Mechanical properties: 
1.  Tensile strength :
Greater tensile strength in m/c direction.
    2. Compressive strength :
The solid extruded ribs perform much more uniformly but carry slightly less load as compared to foamed 
ribs at a given deformation. This is due to lower mass per unit area.
Types of Geonets Thickness
Solid rib extruder
  
5.6mm 
1060
Foamed rib extruder 7.9mm 1700
 
 
 
 
 
 
 
 
 
 
file:///D|/Dr.patra/ground_improvement_techniques/lecture29/29_2.htm (1 of 2) [10/12/2011 11:56:31 AM]
Objectives_template
 
 
 
 
 
 
 
file:///D|/Dr.patra/ground_improvement_techniques/lecture29/29_2.htm (2 of 2) [10/12/2011 11:56:31 AM]
Page 4


Objectives_template
 Module 10:Design methods of Geogrids, Geonets and geomembranes 
 Lecture 29:Geonet properties and test methods 
 
 
The Lecture Contains: 
Applications
 
 
 
 
 
 
 
 
file:///D|/Dr.patra/ground_improvement_techniques/lecture29/29_1.htm [10/12/2011 11:56:31 AM]
Objectives_template
 Module 10:Design methods of Geogrids, Geonets and geomembranes 
 Lecture 29:Geonet properties and test methods 
 
GEONETS
Formed by a continuous extrusion process into a net like configuration of intersecting ribs 
Figure 29.1
?     Geonets consisting of extruded solid ribs.                                         
?     Consisting of extruded solid ribs hence greater flow rate.
?     Made from drawn solid ribs, which allows for vertical rib intersections to be perpendicular, hence 
higher normal pressure.
Geonet properties and Test Methods:
Physical properties – Thickness, mass per unit area        
Mechanical properties: 
1.  Tensile strength :
Greater tensile strength in m/c direction.
    2. Compressive strength :
The solid extruded ribs perform much more uniformly but carry slightly less load as compared to foamed 
ribs at a given deformation. This is due to lower mass per unit area.
Types of Geonets Thickness
Solid rib extruder
  
5.6mm 
1060
Foamed rib extruder 7.9mm 1700
 
 
 
 
 
 
 
 
 
 
file:///D|/Dr.patra/ground_improvement_techniques/lecture29/29_2.htm (1 of 2) [10/12/2011 11:56:31 AM]
Objectives_template
 
 
 
 
 
 
 
file:///D|/Dr.patra/ground_improvement_techniques/lecture29/29_2.htm (2 of 2) [10/12/2011 11:56:31 AM]
Objectives_template
 Module 10:Design methods of Geogrids, Geonets and geomembranes 
 Lecture 29:Geonet properties and test methods 
 
Geonets 
(3) Shear strength
(4) Hydraulic properties:
Transmissivity or in plane hydraulic property is greater than geotextiles and Geogrids.
Allowable flow rate:
Flow rate is a primary factor.
 = Allowable flow rate as obtained by laboratory testing
 = Allowable flow rate as obtained from design of the actual system
 
Factor of safety value
Application Area
Retaining walls,seeping rocks and soil 
slopes.
1.3 to 1.5 1.2 to 1.4 1.1 to 1.5 1.0 to 1.5
Drainge blanket 1.3 to 1.5 1.2 to 1.4 1.0 to 1.2 1.0 to 1.2
Sports field 1.0 to 1.2 1.0 to 1.2 1.0 to 1.2 1.1 to 1.3
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
file:///D|/Dr.patra/ground_improvement_techniques/lecture29/29_3.htm (1 of 2) [10/12/2011 11:56:32 AM]
Page 5


Objectives_template
 Module 10:Design methods of Geogrids, Geonets and geomembranes 
 Lecture 29:Geonet properties and test methods 
 
 
The Lecture Contains: 
Applications
 
 
 
 
 
 
 
 
file:///D|/Dr.patra/ground_improvement_techniques/lecture29/29_1.htm [10/12/2011 11:56:31 AM]
Objectives_template
 Module 10:Design methods of Geogrids, Geonets and geomembranes 
 Lecture 29:Geonet properties and test methods 
 
GEONETS
Formed by a continuous extrusion process into a net like configuration of intersecting ribs 
Figure 29.1
?     Geonets consisting of extruded solid ribs.                                         
?     Consisting of extruded solid ribs hence greater flow rate.
?     Made from drawn solid ribs, which allows for vertical rib intersections to be perpendicular, hence 
higher normal pressure.
Geonet properties and Test Methods:
Physical properties – Thickness, mass per unit area        
Mechanical properties: 
1.  Tensile strength :
Greater tensile strength in m/c direction.
    2. Compressive strength :
The solid extruded ribs perform much more uniformly but carry slightly less load as compared to foamed 
ribs at a given deformation. This is due to lower mass per unit area.
Types of Geonets Thickness
Solid rib extruder
  
5.6mm 
1060
Foamed rib extruder 7.9mm 1700
 
 
 
 
 
 
 
 
 
 
file:///D|/Dr.patra/ground_improvement_techniques/lecture29/29_2.htm (1 of 2) [10/12/2011 11:56:31 AM]
Objectives_template
 
 
 
 
 
 
 
file:///D|/Dr.patra/ground_improvement_techniques/lecture29/29_2.htm (2 of 2) [10/12/2011 11:56:31 AM]
Objectives_template
 Module 10:Design methods of Geogrids, Geonets and geomembranes 
 Lecture 29:Geonet properties and test methods 
 
Geonets 
(3) Shear strength
(4) Hydraulic properties:
Transmissivity or in plane hydraulic property is greater than geotextiles and Geogrids.
Allowable flow rate:
Flow rate is a primary factor.
 = Allowable flow rate as obtained by laboratory testing
 = Allowable flow rate as obtained from design of the actual system
 
Factor of safety value
Application Area
Retaining walls,seeping rocks and soil 
slopes.
1.3 to 1.5 1.2 to 1.4 1.1 to 1.5 1.0 to 1.5
Drainge blanket 1.3 to 1.5 1.2 to 1.4 1.0 to 1.2 1.0 to 1.2
Sports field 1.0 to 1.2 1.0 to 1.2 1.0 to 1.2 1.1 to 1.3
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
file:///D|/Dr.patra/ground_improvement_techniques/lecture29/29_3.htm (1 of 2) [10/12/2011 11:56:32 AM]
Objectives_template
 
file:///D|/Dr.patra/ground_improvement_techniques/lecture29/29_3.htm (2 of 2) [10/12/2011 11:56:32 AM]
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