One-dimensional Consolidation of Thawing Soils

Morgenstern, N. R.; Nixon, John F.

doi:10.1139/t71-057

Cited by 206 publications

(130 citation statements)

References 2 publications

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“…However, thawing of ice-rich fine-grained soils causes thaw consolidation, raised pore pressures, reduced effective stresses, and in consequence, lowered soil shear strength (e.g. Morgenstern and Nixon, 1971;Harris, 2007). As a result of this, mass movement processes are particularly important.…”

Section: Thaw-related Mass Movement Processes: Solifluction and Debrimentioning

confidence: 99%

Permafrost and climate in Europe: Monitoring and modelling thermal, geomorphological and geotechnical responses

Harris

Arenson

Christiansen³

et al. 2009

Earth-Science Reviews

574

361

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We present a review of the changing state of European permafrost within a spatial zone that includes the continuous high latitude arctic permafrost of Svalbard and the discontinuous high altitude mountain permafrost of Iceland, Fennoscandia and the Alps. The paper focuses on methodological developments and data collection over the last decade or so, including research associated with the continent-scale network of instrumented permafrost boreholes established between 1998 and 2001 under the European Union PACE project. Data indicate recent warming trends, with greatest warming at higher latitudes. Equally important are the impacts of shorter-term extreme climatic events, most immediately reflected in changes in active layer thickness. A large number of complex variables, including altitude, topography, insolation and snow distribution, determine permafrost temperatures. The development of regionally calibrated empiricalstatistical models, and physically based process-oriented models, is described, and it is shown that, though more complex and data dependent, process-oriented approaches are better suited to estimating transient effects of climate change in complex mountain topography. Mapping and characterisation of permafrost depth and distribution requires integrated multiple geophysical approaches and recent advances are discussed. We report on recent research into ground ice formation, including ice segregation within bedrock and vein ice formation within ice wedge systems. The potential impacts of climate change on rock weathering, permafrost creep, landslides, rock falls, debris flows and slow mass movements are also discussed. Recent engineering responses to the potentially damaging effects of climate warming are outlined, and risk assessment strategies to minimise geological hazards are described. We conclude that forecasting changes in hazard occurrence, magnitude and frequency is likely to depend on process-based modelling, demanding improved understanding of geomorphological process-response systems and their impacts on human activity. We present a review of the changing state of European permafrost within a spatial zone that includes the continuous high latitude arctic permafrost of Svalbard and the discontinuous high altitude mountain permafrost of Iceland, Fennoscandia and the Alps. The paper focuses on methodological developments and data collection over the last decade or so, including research associated with the continent-scale network of instrumented permafrost boreholes established between 1998 and 2001 under the European Union PACE project. Data indicate recent warming trends, with greatest warming at higher latitudes. Equally important are the impacts of shorter-term extreme climatic events, most immediately reflected in changes in active layer thickness. A large number of complex variables, including altitude, topography, insolation and snow distribution, determine permafrost temperatures. The development of regionally calibrated empiricalstatistical models, and physically based ...

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Section: Thaw-related Mass Movement Processes: Solifluction and Debrimentioning

confidence: 99%

Permafrost and climate in Europe: Monitoring and modelling thermal, geomorphological and geotechnical responses

Harris

Arenson

Christiansen³

et al. 2009

Earth-Science Reviews

574

361

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“…Partial recovery of bank displacements during abovefreezing temperatures (Figure 9) probably resulted from thaw settlement (e.g., Morgenstern and Nixon, 1971;Nixon and Ladanyi, 1978;Andersland and Ladanyi, 2004), with a significant horizontal component. For example, growth of a subvertical ice lens near the top of a gully wall would tend to tilt the adjacent frozen soil slab toward the gully axis.…”

Section: Bank Displacements and Freeze-thawmentioning

confidence: 99%

Bank‐collapse processes in a valley‐bottom gully, western Iowa

Thomas

Iverson

Burkart

2008

Earth Surf Processes Landf

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Widening and bank-slope reduction of a valley-bottom gully in western Iowa was correlated to increasing subsurface flow over a 36-year period. To study bank collapse at this gully, we measured rainfall, air temperature, hydraulic head near the banks and bank movement nearly continuously over a 2-year period. Styles of movement ranged from imperceptible creep to rapid slab collapses preceded by the formation of tension cracks parallel to the gully walls. Bank movement was commonly correlated to rainfall or snowmelt and associated head increases in the banks. If the banks are modelled as a twodimensional slab with an adjacent tension crack partly filled with water, measured heads were sufficient to cause bank failures through reduction of frictional support at the base of the slab. During winter months, air temperature variations across 0°C were correlated with bank movement: during mildly subfreezing periods banks expanded, and most, but usually not all, of this movement was recovered during above-freezing periods. This motion is attributed to frost heave followed by thawing. Deformation of the banks by heaving and thawing during winter may weaken them and prime them for failure during spring rains and snowmelt, when the frequency of mass-wasting events is highest.

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“…ALDs appear in many permafrost landscapes (French, 2007;Lewkowicz, 2007;Lewkowicz and Harris, 2005;McRoberts and Morgenstern, 1974;Rutter et al, 1973;Morgenstern and Nixon, 1971), while MEs have had less attention. The literature and our observations indicate that MEs occur on Ellesmere (Lewkowicz, 2007), Banks, and Melville islands in the Canadian High Arctic and further south in Nunavut and the Northwest Territories in very different vegetation and terrain conditions (Shilts, 1978).…”

Section: Susceptibility Modelling and Landscape Implicationsmentioning

confidence: 99%

“…This addition of moisture, as well as infiltration from late season precipitation, results in high pore-water pressures (PWP) at the base of the active layer (Zoltai and Woo, 1978;French, 2007;Yamamoto, 2014). PWP is the pressure that the water in the voids of saturated soil is under, and influences the shear strength of the soil (Mitchell, 1960;Morgenstern and Nixon, 1971;McRoberts, 1978;Harris, 1981). These pressures can lead to potentially hazardous forms of permafrost degradation and disturbance, and therefore it is important to understand how pore-water pressurization occurs across the landscape, particularly in relation to variable terrain characteristics.…”

Section: Introductionmentioning

confidence: 99%

Determining the terrain characteristics related to the surface expression of subsurface water pressurization in permafrost landscapes using susceptibility modelling

et al. 2017

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Abstract. Warming of the Arctic in recent years has led to changes in the active layer and uppermost permafrost. In particular, thick active layer formation results in more frequent thaw of the ice-rich transient layer. This addition of moisture, as well as infiltration from late season precipitation, results in high pore-water pressures (PWPs) at the base of the active layer and can potentially result in landscape degradation. To predict areas that have the potential for subsurface pressurization, we use susceptibility maps generated using a generalized additive model (GAM). As model response variables, we used active layer detachments (ALDs) and mud ejections (MEs), both formed by high PWP conditions at the Cape Bounty Arctic Watershed Observatory, Melville Island, Canada. As explanatory variables, we used the terrain characteristics elevation, slope, distance to water, topographic position index (TPI), potential incoming solar radiation (PISR), distance to water, normalized difference vegetation index (NDVI; ME model only), geology, and topographic wetness index (TWI). ALDs and MEs were accurately modelled in terms of susceptibility to disturbance across the study area. The susceptibility models demonstrate that ALDs are most probable on hill slopes with gradual to steep slopes and relatively low PISR, whereas MEs are associated with higher elevation areas, lower slope angles, and areas relatively far from water. Based on these results, this method identifies areas that may be sensitive to high PWPs and helps improve our understanding of geomorphic sensitivity to permafrost degradation.

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One-dimensional Consolidation of Thawing Soils

Cited by 206 publications

References 2 publications

Permafrost and climate in Europe: Monitoring and modelling thermal, geomorphological and geotechnical responses

Permafrost and climate in Europe: Monitoring and modelling thermal, geomorphological and geotechnical responses

Bank‐collapse processes in a valley‐bottom gully, western Iowa

Determining the terrain characteristics related to the surface expression of subsurface water pressurization in permafrost landscapes using susceptibility modelling

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