Geo 101 detailed

Geosynthetics 101

Geosynthetics…..

Geosynthetics is the catch all term used to describe a range of generally synthetic products used to solve geotechnical problems or as system with natural earth materials. The term is generally regarded to encompass five main products:

• geotextiles, • geogrids, • geomembranes and geocomposites• Erosion and Sediment Control• MSE (Mechanically Stabilized Earth) Walls

Why Do We Use Geosynthetics?Geosynthetics are environmentally friendly.• Save on gravel costs, fuel costs, machine time

and costs over conventional construction methods.

Geosynthetics save money.• Reduced labor costs lead to reduced

construction times and costs.• The use of geosynthetics in applications results

in increased life cycles, traffic benefit ratios (for roads) which have long term economic benefits (reduced rutting, reinforced roads, etc.).

Roles of Geosynthetics…

Applications…..The role of geosynthetics are:

• Separation,

• Filtration,

• Reinforcement,

• Drainage,

• Containment

Different geosynthetics are suited to the various applications, as illustrated here.

Some of the typical uses of Geosynthetics in Applications are shown here.

Industries Served

• Oil and Gas • Industrial / Mining • Municipal / Transportation • Landscape / Irrigation • Forestry • Many others……..

Products

• Geotextiles• Geogrid• Erosion and Sediment Control• Geomembranes• Retaining Wall systems

QUESTIONS??

On what geosynthetics are?

Geotextiles….

• Geotextile Applications - Woven– Separation– Stabilization– Reinforcement– Erosion Control

Woven Geotextiles

Uses of Woven Geotextiles

–Separation application• roadbuilding (general use)• paved and unpaved infrastructure

–Reinforcement• roadbuilding - paved and unpaved• High surface loads i.e.. Parking lots, runways

Uses of Woven Geotextiles

–Sediment Control application• silt fences• CB inlet devices

Geotextile….

• Geotextiles Applications - NonWoven– Sub-surface drainage– Separation– Stabilization– Erosion Control– Geomembrane Protection

Non Woven Geotextiles

Uses of Non-Woven Geotextiles

• Non-wovens– drainage application

• french drains, pipe sock• MSE walls

– separation application• roadbuilding (specific conditions)• parking lots (specific conditions)• remediation projects• weed barrier

Uses of Non-Woven Geotextiles

• Non-woven (cont’d)– erosion control application

• Bridge abutments• underlay for hard armor EC i.e.. Rip Rap

– protective underlay application• installed above and/or below geomembranes in

landfills, lagoons, SW ponds, etc.

Typical French Drain Application

QUESTIONS??

About Woven or NonWoven Geotextiles??

Geogrids……Geogrids: These are discernibly stiffer than

geotextiles and have relatively large voids within the material. Methods of production vary but include extrusion, bonding or interlacing. They can be produced from nearly all polymeric materials.

Types of Geogrids

Geogrids are rated based on properties.

Biaxial – strength in two directions

Uniaxial – strength in one direction -

Biaxial vs. Uniaxial

• Biaxial – strength in two directions or axes. Typically for point load applications.

• Uniaxial – strength in one direction (axes), typically in reinforced earth applications.

QUESTIONS??

About Geogrids?

Erosion and Sediment Control

– Blankets, TRM’s, – silt fence, – CB doughnuts and others

• Roadside slopes, • Interchanges, • drainage channels, • landfills, • and landscaping

• Commonly used b/c of increasing regulations

Uses and types of Erosion and Sediment Control

• Rolled Erosion Control Products (RECP)– Erosion Control Blankets (ECB)

• they have different designs for use on different slopes and conditions

• they hold top soil in place and accelerate vegetative growth

• they help the natural process of erosion control take place after we disturb it

Rolled Erosion Control (ECB’s)

Uses and types of Erosion and Sediment Control

– Turf Reinforcement Mats (TRM’s)• subsurface application that supports the

vegetation’s root system• used in medium to heavy runoff/discharge

slopes and channels• used when the natural vegetation limits are

NOT exceeded

Uses and types of Erosion and Sediment Control

– High Performance TRM’s (HPTRM’s)• subsurface application - slopes and channels

with high flow/discharge• used when natural vegetation limits can not

support the system• can and will replace hard armor systems at

enormous cost savings

Uses and types of Erosion and Sediment Control

• Sediment control– control soils that have already been displaced– catch basin inlet devices (doughnuts and

backers)– silt fence– straw wattles– turbidity curtains

Silt Fence Installation

QUESTIONS??

About Erosion and Sediment Control?

Reinforced Earth Applications

Part I

• REINFORCED EARTH APPLICATIONS – Retaining walls are most

common application– Fundamental design theory,

reinforced earth is independent of facing systems that are used (Lock Block, Keystone™, Allan Block™, Pisa Stone™, etc. etc.)

Reinforced Soil Mass

Cost of SRW (Segmented Retaining Wall) Comparison

Cost comparison of segmental retaining walls is lower when compared with other leading type of wall systems.

Application: High Point, Kelowna

PET UX geogrids, with Keystone™SRW facing

Wall heights of up to 38 feet

Kelowna, BC

6”- coarse blast rock backfill

Keystone Wall Project

Durability Testing was carried out specifically for this type of backfill.

Test results showed that installation damage reduction factors for these grids was far below industry standards for polyester grids.

Keystone Wall Project - Cont’d

QUESTIONS??

On retaining walls?

Part II

Soft Soil Conditions

Roads & Highways

Base Reinforcement

• SOFT or POOR SOIL conditions• Roles are predominantly reinforcement,

separation or drainage – roads, building foundations, pile cap reinforcements– Typical specifications are woven geotextile or biaxial grids

in these applications– Can be used to reduce costs significantly in resource road

applications where granular or solid material is at a premium

Base Reinforcement Applications

Foundation conditions in a marine silt. Both Geotextiles and Geogrids are used in this application in a composite application.

Roads Applications

Base Reinforcement

• Geogrid Laydown

• Arterial Road Reconstruction,

• New Brunswick, Canada

• 125,000 m2

Geogrid Illustration

Unreinforced Reinforced

Vertical PressureWithout Geogrid

Reduced VerticalPressure With Geogrid

Stabilization Through Separation

Without Geotextiles With Geotextiles

Typically woven geotextile would be used, but some specific applications would use non woven geotextile.

QUESTIONS??

About stabilization or reinforcement?

Part III

Uses and Roles of

Geotextiles

Non Woven and Woven

• Geotextiles are used in all five types of applications – filtration, containment, separation, reinforcement, drainage- Non-woven textiles are typically used for

separation, filtration, and drainage and have a higher elongation.

- Woven textiles are used as above, and additionally for filtration and containment due to a higher tensile strength in two directions, and a lesser elongation.

Comparison…..

Non woven WovenNeedle punched – random strand orientation

Strands are oriented to be transverse to each other in a pattern.

High elongation Low elongation

Filtration and erosion control applications Separation and reinforcement applications.

Containment underlay/subgrades/slopes/ septic systems

Roads/highways/subgrades/slopes

Commonly called “filter fabric”, “felt”, etc. Commonly called “tarp”, “trampoline material”, etc.

Geotextiles used to reinforce slope,

-filtration allows water to pass through the textile while the soils remain on the slope.

Applications for Reinforcement

Geotextiles used as a flitration layer between Atlantis™ stormwater systems. – allows water to pass through the system and restrains soil from passing.

Applications

• Textiles are universal in almost every construction project where water/soil separation is an issue.

• Our textiles come in various grades and strengths, to suit all construction needs and meet or drive competitive specifications.

QUESTIONS??

On applications for woven or nonwoven geotextiles?

Part IV - Containment

Uses and Roles of

Liners and Containment Systems

Containment….

• Environmental Applications• Oil Fuel Storage• Water storage• Fertilizers storage• Chemical Storage• Mine tailings• Municipal Waste Applications

Types of Liners

• High Density Polyethylene (HDPE) Membranes

• Low Linear Density Polyethylene (LLDPE)• Geosynthetic Clay Liners (GCL)• Ethylene Propylene Diene Terpolymner

(EDPM)• Poly Vinyl Chloride (PVC)

HDPE Liners

• Comes in varying thicknesses, from 0.5 to 3.5 mm (20 to 200mils). Can be smooth or textured finish.

• Rigid application, site preparation is a concern

• Typical HDPE applications include: agricultural lagoons, storm water ponds, chemical and industrial ponds, sewage lagoons, storage ponds and landfill caps.

HDPE Project

• PolyFlex 60mil HDPE smooth/Textured liner

• Tailings pond (contaminated gypsum)

• RedWater, AB• 340,000 m2

HDPE Project - Cont’d

LLDPE Liners

• LLDPE is a more flexible version of HDPE that can be prefabricated into large panels.

• greater flexibility than HDPE• Suitable where differential or localized

subgrade settlements are expected• leach ponds, landfill closure caps or any

application where elongation or puncture resistance is critical.

LLDPE Project

• PolyFlex 40mil LLDPE textured liner

• Clean Water Containment

• Strathmore, AB• 69,000 sft

LLDPE Project - Cont’d

GCL Liners• GCLs are manufactured liners consisting of bentonite

clays encased between layers of geotextile, providing an engineered alternative to a compacted clay liner (CCL).

• excellent sealing properties and unique self sealing attributes, reducing risk of failure due to adverse field and operating conditions.

• Most GCL projects can be installed using conventional equipment, and regular construction personnel.

• Landfill Liners Ponds and Lagoons Canals Storage Tanks/Secondary Containment

GCL Project

CETCO GCL Liners• bentonite/textile

composite based.• Water Reservoir

application• Vernon, BC• 14,500 m2

GCL Project

GCL Project - Cont’d

Geocomposites

Poly Flex

• Used in containment construction as collection or drainage

• Can be built as geonet, single sided composite, or double sided composite with any thickness of nonwoven geotextile

QUESTIONS??

On liners?

Summary

• Geosynthetics is a rapidly evolving field, with new uses being found every day.

• As the cost of labor increases, geosynthetics becomes a more viable alternative to conventional construction methods.

• Geosynthetics have many advantages to the environment.

Environmental Benefits

• Better utilization of resources over conventional construction – aggregate… asphalt...steel…fuels...labor

• Less disturbance to the earth• Longer design lives• Making things possible that were not

before (IE – muskeg road applications)• Cost savings – all applications.

Solutions...

• We are a solutions based provider. We provide project or customer -based solutions, using geosynthetics, and are available to assist at whatever level is required using the resources available to us.

QUESTIONS??

Thank You for your time!!