Foundations in permafrost soil

(BLDG 6501: FOUNDATION ENGINEERING)

Professor: Dr. Adel Hanna

Student ID

Hossein Khodaverdipoursarbandi 40003814

Introduction

Types of permafrost

Insulation Use

Foundation design

Final considerations

2

Outline

Introduction

Types of permafrost

Insulation Use

Foundation Design

Final consideration

3

Permafrost:• Any soil that has remained continuously frozen for at least 2 years

Where to find?• In U.S.A , Canada and most industrialized nations of the world• Anywhere there is a freezer plant for cold storage ( a frozen

orange juice manufacturing facility)

Outline

Introduction

Types of permafrost

Insulation Use

Foundation Design

Final consideration

4

Outline

Introduction

Types of permafrost

Insulation Use

Foundation Design

Final consideration

5

Outline

Introduction

Types of permafrost

Insulation Use

Foundation Design

Final consideration

6

Types of permafrost:• Thaw-stable: A soil whose water content is at saturation

or less (safe to build)• Thaw-unstable :

If the frozen soil’s moisture content is greater than saturation

additional space is required for the excess ice (water when it thaws)

When this soil thaws, soil grains sink until they are resting against each other

This overall consolidation= thaw-instability

Settlement of the surface and foundation failures

Outline

Introduction

Types of permafrost

Insulation Use

Foundation Design

Final consideration

7

Outline

Introduction

Types of permafrost

Literature Review

Component Design

Energy Modeling

Wood-framed VS ICFs

Conclusion

References

8

Outline

Introduction

Types of permafrost

Insulation Use

Foundation Design

Final consideration

9

Proper Materials for insulationMaterial Discription Benefits drawbacks

Fiberglass Most commonly modern

insulation material

High thermal resistance, relatively inexpensive, resist mold an

fungus ,easy to install

Little resistance to moisture

Foam polystyrene

(XEPS)

Widely used in construction

for intrusion water and in buried situation, high water resistance insulation, ability to maintain its

thickness under load

Very little losing thermal resistance at some adverse

applications

Molded polystyrene board (EPS)

A cohesive solid with variable

density

More water resistance than XEPS, Its voids provide a path to enter to the board and absorb water

Foamed polyurethane

Unique advantages for

special buildings

Ability of spraying makes it attractive for filling cracks and

sealing openings, stud spaces in pre-built wall sections, One of the

highest thermal resistance

Lower thermal conductivity before

aging, expensive, open-cell-

structure, easily damaged during

construction

Outline

Introduction

Types of permafrost

Insulation Use

Foundation Design

Final consideration

10

Slurried Pile Foundation:• Developed conventional foundation• Piles embedded to permafrost• Piles extend above the surface to raise the building off the

ground (at least 2ft, 0.6m)• Adfreeze bond in the permafrost layer provides required

support for piles (heaving force)• Adfreeze bond in active layer can be eliminated by using

sleeves or coating on the piles• Expensive foundation but far less costly than remedial

actions

Outline

Introduction

Types of permafrost

Insulation Use

Foundation Design

Final consideration

11

Outline

Introduction

Types of permafrost

Insulation Use

Foundation Design

Final consideration

12

Driven piles:• Steel pipe piles driven into frozen soil• When soil is relatively dry, uniform ,fine grained material• Pile driving difficulty increases with decreasing soil tempreture Load capacity:• Long settlement of pile is called Creep• Pile should keep the secondary creep to prevent deformationPile lenghth• The depth of pile into permafrost should not be less than twice the

thickness of active layerAdfreeze bond strength calculation• The temperature dependant• Colder temperature = stronger adfreeze bondShallow foundation• When neither drilling nor driving equipment is available• Not as reliable as deep piles

Outline

Introduction

Types of permafrost

Insulation Use

Foundation Design

Final consideration

13

Outline

Introduction

Types of permafrost

Insulation Use

Foundation Design

Final consideration

14

Natural convection pile foundation:• To increase the rate of heat out of the soil• Enhancing the ability of permafrost to survive summer or

other increased heat input• Without the aid of external power • Classified as either 1.open or 2.closed (single-phase or

two phase)

Outline

Introduction

Types of permafrost

Insulation Use

Foundation Design

Final consideration

15

Outline

Introduction

Types of permafrost

Insulation Use

Foundation Design

Final consideration

16

Surface foundation:The post and pad foundation

Outline

Introduction

Types of permafrost

Insulation Use

Foundation Design

Final consideration

17

Outline

Introduction

Types of permafrost

Insulation Use

Foundation Design

Final consideration

The adjustable post and pad foundation

Rigid three dimensional truss foundation

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Outline

Introduction

Types of permafrost

Insulation Use

Foundation Design

Final consideration

Air flow beneath the elevated foundation• all elevated foundations rely on free circulation of air

beneath the building to protect the permafrost• Preventing debris or snow to accumulate there• Skirting around the building can destroy the function of air

flow

The Surrounding Site• The surrounding area in the immediate vicinity of the

building must be cleared• The maintenance problems of water and sewer lines

connected to the building

Access to the site• The driveway connected to the building should be covered

by a thick layer of non-frost-susceptible fill and it is better to be on the north or northeast of the building (less sun)

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