C-Change in GEES Changing Permafrost Environments

C-Change in GEES Changing Permafrost Environments
Session Six: Development Problems and Engineering Solutions Dr Richard Waller, Keele University, C-Change in GEES: Changing Permafrost Environments – Geotechnical Problems

How to use the teaching slides
These slides are not intended to form a complete lecture on the session topic. These resources are designed to suggest a framework to help tutors develop their own lecture material The resource slides comprise where appropriate; key points, case studies, images, references and further resources. There are limited case studies included. Students can develop their own portfolio of case studies as part of coursework activities These resources may be used for educational purposes only, for other uses please contact the author These slides were last updated in February 2010 Dr Richard Waller, Keele University, C-Change in GEES: Changing Permafrost Environments – Geotechnical Problems 2

Dr Richard Waller, Keele University, r.i.waller@esci.keele.ac.uk
Disclaimer Links within this presentation may lead to other sites. These are provided for convenience only. We do not sponsor, endorse or otherwise approve of any information or statements appearing in those sites. The author is not responsible for the availability of, or the content located on or through, any such external site. While every effort and care has been taken in preparing the content of this presentation, the author disclaims all warranties, expressed or implied, as to the accuracy of the information in any of the content. The author also (to the extent permitted by law) shall not be liable for any losses or damages arising from the use of, or reliance on, the information. The author is also not liable for any losses or damages arising from the use of, or reliance on sites linked to this site, or the internet generally. Pictures, photographs and diagrams within this presentation have been produced by the author unless otherwise stipulated No content within this resource is knowingly an infringement of copyright. Any infringement can be immediately rectified on notification of the author of the resource Dr Richard Waller, Keele University, C-Change in GEES: Changing Permafrost Environments – Geotechnical Problems 3

Session Outline Subsidence Problems Engineering Solutions Water Supply and Waste Disposal R.I. Waller Dr Richard Waller, Keele University, C-Change in GEES: Changing Permafrost Environments – Geotechnical Problems

Introduction Developing permafrost environments is associated with a unique set of problems. Majority associated with the intrinsic thermal sensitivity of permafrost. Major problems in areas associated with frost-susceptible and ice-rich materials. Engineering solutions exist, but they tend to be extremely costly. Additional problems associated with water supply and waste disposal. Dr Richard Waller, Keele University, C-Change in GEES: Changing Permafrost Environments – Geotechnical Problems 5

Major difficulty associated with developing permafrost
environments, is the extremely harsh climate. We’ll take this for granted and focus on the problems associated with the operation of permafrost processes. R.I. Waller Grave of a gold prospector who “froze to death” near Atlin, northern British Columbia. Dr Richard Waller, Keele University, C-Change in GEES: Changing Permafrost Environments – Geotechnical Problems 6

The Principal Problems
Frost heave associated with freeze-back of the active layer during the winter. Thaw subsidence - thaw of ice-rich permafrost and associated terrain disturbance. Hydrological and groundwater characteristics - problems of water supply and waste disposal in particular. R.I. Waller Retrogressive thaw slump on Summer Island, Mackenzie Delta Dr Richard Waller, Keele University, C-Change in GEES: Changing Permafrost Environments – Geotechnical Problems 7

Thermal Disturbance Major construction problem, which relates to the thermal sensitivity of permafrost. Modification of the ground thermal regime can lead to two problems: 1) Thaw subsidence: ground warming; increase in depth of active layer. 2) Frost heave: can occur seasonally (within active layer) or more permanently (permafrost aggradation). R.I. Waller N.B. Only a problem where material is frost susceptible and resulting frozen ground is ice-rich. Dr Richard Waller, Keele University, C-Change in GEES: Changing Permafrost Environments – Geotechnical Problems 8

Surface boundary conditions
PERMAFROST THICKNESS CLIMATE GROUND SURFACE TEMP. THERMAL REGIME Surface energy balance Ground thermal properties (+time) Surface boundary conditions Human activities cause problems by changing the surface boundary conditions and modifying the surface energy balance. Dr Richard Waller, Keele University, C-Change in GEES: Changing Permafrost Environments – Geotechnical Problems 9

Thaw Subsidence Disturbance of surface boundary conditions usually results in an increase in surface temperatures and thermokarst development. Common causes: Disturbance or clearance of vegetation Associated loss of surface insulation. Construction of heated building. Stripping of surface materials: e.g. to supply construction materials. Movement of vehicles: seismic lines from 1950s still visible in ice-rich tundra regions. Dr Richard Waller, Keele University, C-Change in GEES: Changing Permafrost Environments – Geotechnical Problems 10

Flow chart illustrating the varied causes of thermokarst
Figure From: French, H.M The Periglacial Environment (3rd ed.). Wiley & Sons, Chichester(p.188). © Wiley and Sons Dr Richard Waller, Keele University, C-Change in GEES: Changing Permafrost Environments – Geotechnical Problems 11

Dawson City was the first city to be built on ice-rich permafrost in 1898 Construction of heated buildings had inevitable consequences... Dr Richard Waller, Keele University, C-Change in GEES: Changing Permafrost Environments – Geotechnical Problems 12

Stripping of Surface Materials Case Study: Banks Island
Relates to construction of an airstrip between Thawed surface gravels were stripped and moved by bulldozer to provide a level runway. Subsequent thaw of underlying ice-rich sands with 20-35% volumetric excess ice content (and ice wedges). Development of hummocky thermokarst terrain and widespread landscape disturbance. Thaw lakes on Banks Island French, H.M. (1975) Man-induced thermokarst, Sachs Harbour Airstrip, Banks Island, Northwest Territories. Canadian Journal of Earth Sciences, 12, Dr Richard Waller, Keele University, C-Change in GEES: Changing Permafrost Environments – Geotechnical Problems 13

After: MacKay, J.R. (1970) ‘Disturbances to the tundra and forest tundra environment of the western Arctic’ Canadian Geotechnical Journal Illustration of the volumetric loss and thaw subsidence associated with terrain disturbance and the melting of excess ice. Dr Richard Waller, Keele University, C-Change in GEES: Changing Permafrost Environments – Geotechnical Problems 14

Human activities (e.g. shading associated with unheated buildings) can also result in a reduction in ground temperature and problems associated with long-term frost heave… Surface frost heave associated with the growth of needle ice (R I Waller) Dr Richard Waller, Keele University, C-Change in GEES: Changing Permafrost Environments – Geotechnical Problems 15

Frost Heave Frost heave associated with seasonal freezing of active layer can prove problematic: A. Thrust perpendicular to the freezing front. B. Freezing behind a wall can result in its destruction. C. “Frost jacking” – frost heave literally lifts structures out of the ground. Figure from: Cooke, R.U. & Doornkamp, J.C Geomorphology in Environmental Management (2nd ed.). OUP, Oxford. © Oxford University Press Dr Richard Waller, Keele University, C-Change in GEES: Changing Permafrost Environments – Geotechnical Problems 16

Frost jacking of a pipeline in the Russian Arctic
Courtesy of Dr. Thomas L. White "Pipelines in Permafrost and Freezing Ground" Dr Richard Waller, Keele University, C-Change in GEES: Changing Permafrost Environments – Geotechnical Problems

Engineering Solutions
Heated fuel oil tanks situated on gravel pads with thermosyphons, northern Alaska (R.I. Waller) Dr Richard Waller, Keele University, C-Change in GEES: Changing Permafrost Environments – Geotechnical Problems 18

Controlling Factors Three factors determine the potential severity of permafrost degradation: Ice content of the permafrost (notably presence/absence of excess ice). Thickness and insulating qualities of the surface vegetation. Duration and warmth of the summer thaw period. R.I. Waller Must be considered when assessing the risk and planning remedial measures. Dr Richard Waller, Keele University, C-Change in GEES: Changing Permafrost Environments – Geotechnical Problems 19

Assessing Site Conditions
Massive bedrock: Ice contents usually low and permafrost problems can be largely ignored. Ice-rich sediments: “Frost-susceptible” organic or unconsolidated sediments frequently contain large volumes of ice. Special measures must be taken. Best to preserve pre-existing thermal regime. i.e. prevention better than cure. Appropriate solution depends upon site conditions and financial resources available. Dr Richard Waller, Keele University, C-Change in GEES: Changing Permafrost Environments – Geotechnical Problems 20

Fundamental design options when building on permafrost.
Figure from: Bennett, M.R. & Doyle, P Environmental Geology. Wiley & Sons, Chichester. © Wiley and Sons Dr Richard Waller, Keele University, C-Change in GEES: Changing Permafrost Environments – Geotechnical Problems 21

Gravel Pads Most common solution is to build structure on a pad of coarse-grained sediment. Physically separates structure from the permafrost. Coarse-grained material is non-frost susceptible - limits frost heave. Commonly used in construction of roads, airstrips, buildings etc. Needs careful design – aim to provide insulation equivalent to pre-existing surface materials. R.I. Waller Heated fuel oil tank resting on a ventilated, gravel pad. Inuvik, Canadian N.W.T. Dr Richard Waller, Keele University, C-Change in GEES: Changing Permafrost Environments – Geotechnical Problems 22

Gravel Pad Design If too thin (a): level of insulation will be reduced, seasonal temperature fluctuations will increase, and active layer will deepen, causing subsidence. If too thick (b): level of insulation is increased, fluctuations will decrease and active layer will thin, leading to frost heave. Figure from: French, H.M The Periglacial Environment (3rd ed.). Wiley & Sons, Chichester. © Wiley and Sons Dr Richard Waller, Keele University, C-Change in GEES: Changing Permafrost Environments – Geotechnical Problems 23

Additional Solutions Piles: If structure is likely to generate large amounts of heat, whole structure is usually mounted on piles driven into the permafrost. Allows circulation of air and greater physical separation. Thermosyphons: Passive heat pumps can be used to enhance the degree of cooling. Used in important structures such as dams. R.I. Waller Houses in Nuiqsut (Alaska) built on wooden piles Dr Richard Waller, Keele University, C-Change in GEES: Changing Permafrost Environments – Geotechnical Problems 24

Thermosyphons Passive heat pumps used to enhance cooling of foundations. Sealed pipe containing a volatile fluid that transfers heat in response to a thermal gradient (e.g. Ammonia, pressurised CO2). Two parts: Evaporator (buried in ground). Condensor (above ground). When evaporator (ground) is warmer than the condensor (air): Fluid evaporates (removes heat). Rises into the condensor and condenses (releases heat). Sinks back into the evaporator. R.I. Waller Thermosyphons providing additional cooling around a fuel oil tank Dr Richard Waller, Keele University, C-Change in GEES: Changing Permafrost Environments – Geotechnical Problems

Water Supply and Waste Disposal
Utilidor and “utilidettes” in Inuvik, Canadian NWT (R.I. Waller) Dr Richard Waller, Keele University, C-Change in GEES: Changing Permafrost Environments – Geotechnical Problems 26

Municipal Services Provision of water supply and sewage disposal services is a major problem in permafrost areas. Provision of a clean water supply is problematic: Suprapermafrost water: easily contaminated, only occurs in the summer. Intrapermafrost water: often highly mineralised. Consequent reliance upon subpermafrost water either sourced through springs or wells. When not available, lakes are utilised. Great care must be taken to ensure they’re not contaminated. Dr Richard Waller, Keele University, C-Change in GEES: Changing Permafrost Environments – Geotechnical Problems 27

Water Supply Pipes cannot be simply laid underground!
Best known solution is to run pipes above ground in insulated boxes. So-called “utilidors” are a famous permafrost innovation. BUT: extremely costly to build and maintain. Therefore only viable for large developments. Where site conditions are less severe, pipes are laid in trenches backfilled with gravel. In small communities, water is simply trucked to houses. R.I. Waller Utilidor system in Inuvik, Canadian Northwest Territories. Dr Richard Waller, Keele University, C-Change in GEES: Changing Permafrost Environments – Geotechnical Problems 28

Waste Disposal Approaches to waste disposal depend upon the size of the settlement. Simplest method is the “honey bucket” - effluent collected in plastic bags and dumped. Majority of houses in smaller communities now have septic tanks which are periodically emptied by truck. Insulated and heated to prevent effluent freezing! Waste usually disposed into the sea or coastal lagoons with little or no treatment... Dr Richard Waller, Keele University, C-Change in GEES: Changing Permafrost Environments – Geotechnical Problems 29

Lecture Summary Ignorance of permafrost processes has in the past led to considerable destruction and disruption of human infrastructure. Variety of engineering solutions have been designed to preserve the delicate ground thermal regime and ground ice and thereby prevent frost heave and thaw consolidation. Special arrangements still have to be made for water supply and waste disposal. Permafrost regions can be settled successfully, but at a price… Dr Richard Waller, Keele University, C-Change in GEES: Changing Permafrost Environments – Geotechnical Problems 30

References Bennett, M.R. & Doyle, P Environmental Geology. Wiley & Sons, Chichester. Cooke, R.U. & Doornkamp, J.C Geomorphology in Environmental Management (2nd ed.). OUP, Oxford. French, H.M The Periglacial Environment (3rd ed.). Wiley & Sons, Chichester. Harris, S.A The Permafrost Environment. Croom Helm, Beckenham. Williams, P.J. & Smith, M.W The Frozen Earth. Studies in Polar Research. CUP, Cambridge. Dr Richard Waller, Keele University, C-Change in GEES: Changing Permafrost Environments – Geotechnical Problems

This resource was created by the University of Keele and released as an open educational resource through the 'C-change in GEES' project exploring the open licensing of climate change and sustainability resources in the Geography, Earth and Environmental Sciences. The C-change in GEES project was funded by HEFCE as part of the JISC/HE Academy UKOER programme and coordinated by the GEES Subject Centre. This resource is licensed under the terms of the Attribution-Non-Commercial-Share Alike 2.0 UK: England & Wales license ( However the resource, where specified below, contains other 3rd party materials under their own licenses. The licenses and attributions are outlined below: Slide 11 – Flow chart showing the causes of thermokarst from: French, H.M The Periglacial Environment (3rd ed.). Wiley & Sons, Chichester, is the copyright of Wiley and Sons. Permission should be sought from the copyright holders prior to re-use Slide 16 – Figure showing frost heave from: Cooke, R.U. & Doornkamp, J.C Geomorphology in Environmental Management (2nd ed.). OUP, Oxford, is the copyright of Oxford University Press. Permission should be sought from the copyright holders prior to re-use Slide 21 – Figure showing design options when building on permafrost from: Bennett, M.R. & Doyle, P Environmental Geology. Wiley & Sons, Chichester, is the copyright of Wiley and Sons. Permission should be sought from the copyright holders prior to re-use Slide 23 – Figure showing gravel pad design from: French, H.M The Periglacial Environment (3rd ed.). Wiley & Sons, Chichester, is the copyright of Wiley and Sons. Permission should be sought from the copyright holders prior to re-use The name of Keele University and its logos are unregistered trade marks of the University. The University reserves all rights to these items beyond their inclusion in these CC resources. The JISC logo, the C-change logo and the logo of the Higher Education Academy Subject Centre for the Geography, Earth and Environmental Sciences are licensed under the terms of the Creative Commons Attribution -non-commercial-No Derivative Works 2.0 UK England & Wales license. All reproductions must comply with the terms of that license

Item Metadata Author Dr Richard Waller Stephen Whitfield
Institute – Owner Keele University, School of Physical and Geographical Sciences Title Geotechnical Problems PowerPoint Presentation Date Created March 2010 Description Part Six of Changing Permafrost Environments Educational Level 3 Keywords (Primary keywords – UKOER & GEESOER) UKOER, GEESOER, Subsidence, Engineering, Solutions, Development, Water Supply, Waste Disposal Creative Commons License Attribution-Non-Commercial-Share Alike 2.0 UK: England & Wales

C-Change in GEES Changing Permafrost Environments

Similar presentations

Presentation on theme: "C-Change in GEES Changing Permafrost Environments"— Presentation transcript:

Similar presentations

About project

Feedback

Log in

Auth with social network:

C-Change in GEES Changing Permafrost Environments

Similar presentations

Presentation on theme: "C-Change in GEES Changing Permafrost Environments"— Presentation transcript:

Similar presentations

About project

Feedback