uu.seUppsala University Publications
Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Kinematics and Internal Deformation of Granular Slopes
Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences. (Solid Earth Geology)
2014 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Flow-like mass movement is the most destructive landslide and causes loss of lives and substantial property damage throughout the world every year. This thesis focuses on the spatial and temporal changes of the mass movement in terms of velocity and displacement within the failure mass, and the spatial and temporal distribution of the three dimensional internal deformation of the granular slopes using discrete element method, physical experiments, and natural landslides. We have also studied the effect of weak horizons on the kinematics and internal deformation of granular slopes. Numerical model results show the following features related to a failure mass. The failure mass flows downwards in an undulating pattern with a distinctive velocity heterogeneity. Dilatation within the failure mass is strongly dependent on its mechanical properties. A larger mass moves downslope and the mass moves faster and further in the model with lower internal friction and cohesion. The presence of weak horizons within the granular slope strongly influences displacement, location of the failure surface, and the amount of the failure mass. In addition, results from analogue models and natural landslides are used to outline the mode of granular failure. The collapse of granular slopes results in different-generation extensional faults in the back of the slope, and contractional structures (overturned folds, sheath folds and thrusts) in the toe of the slope. The first-generation normal faults with a steep dip (about 60º) cut across the entire stratigraphy of the slope, whereas the later-generation normal faults with a gentle dip (about 40º) cut across the shallow units. The nature of the runout base has a significant influence on the runout distance, topography and internal deformation of a granular slope. Good agreements are found between models and nature for the collapse of granular slopes in terms of the similar structural distribution in the head and toe of the failure mass and different generations of failure surfaces. The presence of a weak horizon within the granular slope has a significant influence on the granular failure and three dimensional internal deformation of the failure mass.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2014. , 39 p.
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 1153
Keyword [en]
granular flow, kinematics, internal deformation, particle flow method, analogue modeling, natural landslides
National Category
Geology
Research subject
Earth Science with specialization in Mineral Chemistry, Petrology and Tectonics
Identifiers
URN: urn:nbn:se:uu:diva-223792ISBN: 978-91-554-8968-7 (print)OAI: oai:DiVA.org:uu-223792DiVA: diva2:714128
Public defence
2014-06-13, Hambergsalen, Geocentrum, Villavägen 16, Uppsala, 10:00 (English)
Opponent
Supervisors
Available from: 2014-05-23 Created: 2014-04-25 Last updated: 2014-06-30
List of papers
1. Kinematics and internal deformation of granular slopes: insights from discrete element modeling
Open this publication in new window or tab >>Kinematics and internal deformation of granular slopes: insights from discrete element modeling
2013 (English)In: Landslides: Journal of the International Consortium on Landslides, ISSN 1612-510X, E-ISSN 1612-5118, Vol. 10, no 2, 139-160 p.Article in journal (Refereed) Published
Abstract [en]

The kinematics and internal deformation of a failure mass during the flow-like moving off a slope were monitored and quantified with the particle flow method in this study. Two kinds of cases were investigated, noncohesive and cohesive granular slopes. Three different internal friction angles and cohesive strengths were considered to systematically investigate their effect on the kinematics and internal deformation of the failure mass. We analyzed the movement within the failure mass and concluded that the mass moves downwards in an undulating pattern. The slope surface topography changes from a straight line to curved lines with slope breaks in a convex geometry. In addition, dilatation within the failure mass, which deforms internally and heterogeneously, is strongly dependent on its mechanical properties. A larger mass moves downslope, and the mass moves faster and further in the model with lower internal friction and cohesion. The internal friction and cohesion have a positive impact on porosity and two-dimensional (or volumetric in 3D) strain within the failure mass.

Keyword
Granular flow, Particle flow method, Failure mass, Internal deformation, Kinematics
National Category
Geology Earth and Related Environmental Sciences
Research subject
Earth Science with specialization in Mineral Chemistry, Petrology and Tectonics
Identifiers
urn:nbn:se:uu:diva-175537 (URN)10.1007/s10346-012-0318-8 (DOI)000317141600003 ()
Available from: 2013-04-05 Created: 2012-06-08 Last updated: 2017-12-07Bibliographically approved
2. The impact of a weak horizon on kinematics and internal deformation of a failure mass using discrete element method
Open this publication in new window or tab >>The impact of a weak horizon on kinematics and internal deformation of a failure mass using discrete element method
2013 (English)In: Tectonophysics, ISSN 0040-1951, E-ISSN 1879-3266, Vol. 586, 95-111 p.Article in journal (Refereed) Published
Abstract [en]

Weak horizons within slopes may induce and/or accelerate failure of slopes. In this study, we focus on the effect of orientation, location and dimension of a weak horizon on the mode and kinematics of downslope movement of a failure mass using discrete element method. Two kinds of cases with weak horizons were studied, one unstable homogeneous slope with low shear strength (c = 50 kPa, μ = 0.57) and two stable homogeneous slopes with high shear strength (c = 60 kPa, μ = 0.57 or c = 50 kPa, μ = 0.7). In the three set of slope models, there was a weak horizon with a finite thickness embedded within the slope. In each set of slope models, two different thicknesses and locations for the weak horizons were considered to systematically investigate the effect of these parameters on the mass movement. In addition, the dip of the weak horizon was changed where in some models, it was parallel to the slope and in others it was dipping either steeper or gentler than the slope. We analyzed both kinematics and internal deformation of the failure mass in all models and conclude that the presence and geometry (i.e., thickness, location and dip) of a weak horizon changes the mode and kinematics of mass movement and governs the location of the failure surface.

Place, publisher, year, edition, pages
Elsevier, 2013
Keyword
slope stability; weak horizon; particle flow method; internal deformation; kinematics
National Category
Earth and Related Environmental Sciences Geology
Research subject
Earth Science with specialization in Mineral Chemistry, Petrology and Tectonics
Identifiers
urn:nbn:se:uu:diva-188513 (URN)10.1016/j.tecto.2012.11.009 (DOI)000316591200007 ()
Available from: 2012-12-17 Created: 2012-12-17 Last updated: 2017-12-06Bibliographically approved
3. Kinematics and 3-D internal deformation of granular slopes: analogue models and natural landslides
Open this publication in new window or tab >>Kinematics and 3-D internal deformation of granular slopes: analogue models and natural landslides
Show others...
2013 (English)In: Journal of Structural Geology, ISSN 0191-8141, E-ISSN 1873-1201, Vol. 53, 27-42 p.Article in journal (Refereed) Published
Abstract [en]

This study uses results from a series of analogue models, and field observations, scanned data and sections of natural landslides to investigate the kinematics and internal deformation during the failure of an unstable slope. The models simulate collapse of granular slopes and focus on the spatial and temporal distribution of their internal structures. Using a series of systematically designed models, we have studied the effect of friction and deformability of the runout base on internal deformation within a granular slope. The results of these different models show that the collapse of granular slopes resulted in different-generation extensional faults at the back of the slope, and contractional structures (overturned folds, sheath folds and thrusts) at the toe of the slope. The failure surfaces and the volume of the failure mass changed both spatially and temporally. Younger failure surfaces formed in the back of the older ones by incorporating additional new material from the head of the slope. Our model results also show that the nature of the runout base has a significant influence on the runout distance, topography and internal deformation of a granular slope. Model results are compared with natural landslides where local profiles were dug in order to decipher the internal structures of the failure mass. The natural cases show similar structural distribution at the head and toe of the failure mass. As in model results, our field observations indicate the presence of at least two generations of failure surfaces where the older ones are steeper.

Keyword
Granular slopes, Analogue models, Landslides, Internal deformation, Runout base
National Category
Geology Earth and Related Environmental Sciences
Research subject
Earth Science with specialization in Mineral Chemistry, Petrology and Tectonics
Identifiers
urn:nbn:se:uu:diva-188231 (URN)10.1016/j.jsg.2013.05.010 (DOI)000322805600003 ()
Available from: 2012-12-14 Created: 2012-12-14 Last updated: 2017-12-06Bibliographically approved
4. Analogue modeling of the collapse of non-homogeneous granular slopes along weak horizons
Open this publication in new window or tab >>Analogue modeling of the collapse of non-homogeneous granular slopes along weak horizons
2014 (English)In: Tectonophysics, ISSN 0040-1951, E-ISSN 1879-3266, Vol. 632, 76-95 p.Article in journal (Refereed) Published
Abstract [en]

In this study, we use results of analogue models to investigate the effect of the orientation, location and thickness of a weak horizon on the stability/failure, kinematics and internal deformation of a granular slope. The models are systematically designed to simulate the collapse of non-homogeneous granular slopes by focusing on the spatial and temporal distribution of their internal deformation. Model results show that the presence of a weak horizon embedded within the granular slope has a significant influence on the granular failure which is accommodated through different generation pulses that successively decrease in volume. However, the dip and stratigraphic location of the weak horizon dictate whether the weak horizon plays a role during the failure or not. When the main failure surface is contained within a weak horizon, the dip and thickness of the weak horizon have a positive effect on the displacement of the failure mass, whereas a shallow-located weak horizon causes larger displacement of the failure mass during the collapse of granular slopes. In addition, the collapse of granular slopes results in formation of different-generation normal faults and shortening structures (folds and thrusts) within the failure mass. The first-generation normal faults with a steep dip (about 60º) cut across the entire stratigraphy of the slope, whereas the later-generation normal faults with a gentle dip (about 40º) cut across the shallow units. The distribution of these internal structures within the failure mass is affected significantly by the orientation, location and thickness of the weak horizon. 

Keyword
Non-homogeneous granular slopes; Analogue models; Landslides; Internal deformation; Weak horizon
National Category
Geology
Research subject
Earth Science with specialization in Mineral Chemistry, Petrology and Tectonics
Identifiers
urn:nbn:se:uu:diva-223785 (URN)10.1016/j.tecto.2014.06.007 (DOI)000343378500007 ()
Available from: 2014-04-25 Created: 2014-04-25 Last updated: 2017-12-05Bibliographically approved

Open Access in DiVA

fulltext(8098 kB)679 downloads
File information
File name FULLTEXT01.pdfFile size 8098 kBChecksum SHA-512
c77dbbce600eceb9c5e241c03fa6183ee302cfd4b93d08616d67cbdbd7b995c5fb76b7a544ee50a26a4e76038abeb3b39c5285059168e293a3cb8e2fac926ed3
Type fulltextMimetype application/pdf
Buy this publication >>

Authority records BETA

Liu, Zhina

Search in DiVA

By author/editor
Liu, Zhina
By organisation
Department of Earth Sciences
Geology

Search outside of DiVA

GoogleGoogle Scholar
Total: 679 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

isbn
urn-nbn

Altmetric score

isbn
urn-nbn
Total: 1080 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf