Monitoring and physical model simulation of a complex slope deformation in neovolcanics in neovolcanics J. R y b á ř & B. K o š ť á k Institute of Rock.

Monitoring andMonitoring and physical model physical model simulation simulation

of a complex slope deformationof a complex slope deformation in neovolcanicsin neovolcanics

J. R y b á ř & B. K o š ť á k

Institute of Rock Structure and MechanicsCzech Academy of Science

Prague, Czech Republic

Čeřeniště landslide – the main Čeřeniště landslide – the main

scarpscarp

Čeřeniště slide - upper part displays individual blocks separated by deep Čeřeniště slide - upper part displays individual blocks separated by deep trenchestrenches

1- scarps and trenches in basalt rocks 2 - recent potential and old landslides 3 – recent

active landslide 4 - outstanding edges in the relief 5 - erosional walls 6 - debris

7 - alluvial sediments 8 - spring 9 - lake 10 - undrained depressions 11 - waterflow 12 - periodically dry creek

Čeřeniště slide – Čeřeniště slide – situation of slope situation of slope

deformationsdeformations

Strange tilted Strange tilted platformplatform with a with a

lakelake

The Labe River CanyonThe Labe River Canyon2km2km: : 140 m a.s.l.140 m a.s.l.

Čeřeniště slide - gČeřeniště slide - geological cross-section through the slope deformation

C r o s s s e c t i o C r o s s s e c t i o n:n:

  Engineering-geological maps - scale 1:2 000, 1:5 000- geomorphological and geologicalmaps 1:10 000- series of longitudinal andtransversal profiles

Monitoring of deformation effects - two highly sensitive mechanico-optical

dilatometric gauges TM71 in the trenches under

main separation wall 

Applied geophysics - three phases: - symmetrical resistance profiling and

vertical electrical probing- spontaneous polarisation SP- radiometry

Geomorphological investigations - to find relation between the evolution

of the Labe River valley andČeřeniště slope deformations

Geological and Quarterly-geology methods and dendrochronology

 Photoplastic physical models - to verify the solutions

I n v e s t i g a t i o n m e t h o d s:I n v e s t i g a t i o n m e t h o d s:

Čeřeniště slide - Čeřeniště slide - 3D field deformation monitoring in scarps using TM713D field deformation monitoring in scarps using TM71

MM oo nn ii tt oo rr ii nn gg::

-0.50

0.50

1.50

2.50

0.00

1.00

2.00

3.00

[m m ] d isp lacem ent x ,y ,z

x

z

y

1997 1998 1999 2000 2001 2002 2003year (decim al)

Č eřeniště 2

-0.50

0.50

1.50

2.50

0.00

1.00

2.00

3.00

[m m ] d isp lacem ent x ,y ,z

x

z

y

1997 1998 1999 2000 2001 2002 2003year (decim al)

Č eřeniště 1

-0.05

0.05

-0.10

0.00

0.10angu lar dev ia tion

1997 1998 1999 2000 2001 2002 2003year (decim al)

Č eřeniště 2[g rad ]

xy

xz

-0.05

0.05

-0.10

0.00

0.10

angu lar devia tion

1997 1998 1999 2000 2001 2002 2003year (decim al)

Č eřeniště 1[g rad ]

xy

xz

• Low value angular deviations registered provide evidence of block arching in scar zone

• Displacements registered at the upper part of Čeřeniště deformation• Component z  represents progressive sinking of rock blocks into the main scar trench • No separation of rock blocks indicated

P h o t o p l a s t i c m o d e l P h o t o p l a s t i c m o d e l s:s:

• made of made of agaragar gels: gels:

agar agar deforms progressively by body weight after horizontal deforms progressively by body weight after horizontal sidewise stress releasesidewise stress release

• models are observed in polarized lightmodels are observed in polarized light

• mmodels produced as odels produced as a a series of individual elastoplasticseries of individual elastoplastic, brittle , brittle layerslayers with slippery plastic intercallations with slippery plastic intercallations

• followingfollowing model is simulating model is simulating a series of basalt lava flowsa series of basalt lava flows with tuff with tuff intercallations in a deformation process of gravitation tectonics intercallations in a deformation process of gravitation tectonics induced by deepening of the Labe River Canyoninduced by deepening of the Labe River Canyon

• tthe erosion process took place in Pleistocene when volcanites were he erosion process took place in Pleistocene when volcanites were cut through completely up to the Cretaceous basementcut through completely up to the Cretaceous basement - t - the Labe he Labe River reached then a level of up to 16 m beneath the present bottom River reached then a level of up to 16 m beneath the present bottom ((140 m a140 m a. . ss. . l.l.) )

P h o t o p l a s t i c m o d e lP h o t o p l a s t i c m o d e l

Upper scar area of the Čeřeniště landslide produced in one of the models

Morphology shows: • separation wall• deep scar• inclined sinking blocks• trenches in the marginal zone (right) • voids under the hill (left)

P h o t o p l a s t i c m o d P h o t o p l a s t i c m o d e le l

platform formation

• complex layered model representing a series of lava flows

• deepening of the Labe River Canyon

formation of wedge-like islands separated by anticlinal shear planes after horizontal stress release

• the wedge-like islands are almost stress free

chance for undisturbed platforms to develop and survive in the heavily deformed slope

Model 30: Evolution in a system of volcanic lava flows after a unilateral deformation release due to the Labe River erosion model time: 0:10:00

P h o t o p l a s t i c m o d P h o t o p l a s t i c m o d e le l

Model 30: Superficial block morphology in the scar area due to continuing evolution in the system of lava flows in the unilatreal release process due to the Labe River erosion

model time: 0:30:00

P h o t o p l a s t i c m o d P h o t o p l a s t i c m o d e le l

competent

competent - incompetent

incompetent

The END...

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