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SLOPE STABILITYITB LECTURE - 2011

From: Das (2002), Principles of Geotechnical Engineering, 5th Ed, Chapter 14.

Perloff, W.H. and Baron, W, Soil Mechanics Principles and Applications, 1976

Landslides:

La Conchita, CA FLEETWOOD MAC

Po Shan Rd, HK

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2011 Toll Semarang-Ungaran KM 5.5

JAKARTA- Kementerian Pekerjaan Umum (PU) mengakui bahwa proyek tol Semarang-Ungaran di ruas Gedawang-Penggaron dibangun di lokasi bekas longsoran.Longsoran itu terjadi sekitar 40 tahun silam. Ketika dibangun tol, lokasi itu diurukdengan ketinggian sekitar 20 meter.Akibatnya, tanah di bawahnya tidak kuat menahan timbunan baru sehinggamenyebabkan ambles. Demikian salah satu kesimpulan tim ahli dari Kementerian PUyang diturunkan ke lokasi proyek untuk meneliti penyebab retak dan amblesnya tol distasiun 5+500, tepatnya di daerah Karangpucung, Banyumanik yang masuk dalamruas Gedawang-Penggaron.

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Toll Semarang – Solo KM 17

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Chili Earthquake, M= 8.8, Febr 27, 2010

Photo: AP

Landslide videos

See the extreme Japanese Landslide http://www.youtube.com/watch?v=23NZTzpw6cYhttp://www.youtube.com/watch?v 23NZTzpw6cY Malaysia slidehttp://www.youtube.com/watch?v=H6Ma0SVjMHA Sultan River Slidehttp://www.youtube.com/watch?v=Qu88wb6gROg Tsunami

// /http://www.youtube.com/watch?v=vT07YWKvehA&feature=fvwrel

http://www.youtube.com/watch?v=5-zfCBCq-8I&feature=relmfu

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http://www.youtube.com/watch?v=XC9AqJlaCj4&feat re=relatedeature=related

Landslide Tsunami

http://www.youtube.com/watch?v=_RMprH-4QC4

http://www.youtube.com/watch?v=w3AdFjklR50

Saidmareh Iran Landslide

The largest landslide that has been identified on Earth's surface is the Saidmareh Landslide located in western Iran The slide occurred about 10 000 Iran. The slide occurred about 10,000 years ago when about 20 cubic kilometers (about 5 cubic miles) of Lower Miocene and Eocene limestone detached along bedding planes and slipped down the north flank of the Kabir Kuh anticline. The maximum vertical descent was about 1600 meters (5250 feet).

The sliding slab was about 15 kilometers (9 miles) wide and had a surface area of about 165 kilometers (64 square miles). Debris from the slide crossed the Karkheh River at the base of the slope and spread across the valley floor. Some material in the slide had a travel distance of over 14 kilometers (9 miles).

http://daveslandslideblog.blogspot.com/2009/07/landslide-of-them-all-saidmareh-iran.html

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SITU GINTUNG

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Earth slide:

Factor of Safety:

f = c’ + ’ tan ’ shearing resistance

f@ failure plane

d = c’d + ’ tan ’d mobilized shearing

@ failure plane

F = c’/c F = [tan ’] / [tan ] Fc = c /cd F = [tan ] / [tan d]

Fs = [c’ + ’ tan ’] / [c’d + ’ tan ’d] if Fc = F

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Infinite Slopes

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Infinite Slopes with Seepage

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Generalized Method of Slices[Perloff, W.H. and Baron, W, Soil Mechanics Principles and Applications, 1976]

Equilibrium equations:

FH = 0; FV = 0; Mo = 0;

3n equations

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simplifying assumptions:

Or, a is assumed to be at mid point or center of gravity of slice

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Bishop’s Ordinary Method of Slices

Equal & in line inter slice inter slice forces

Bishop’s Simplified Method of Slices [ = 0]

and M = 0

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Spencer (1967) [f(x) = constant]

All inter slice forces are parallel, the inclination, is one of the unknowns.

N acts on the center of the base of each slice FH = 0; FV = 0; Mo = 0

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Morgenstern & Price [1965]

T = f(x) E where is an unknown scaling factor,

f( ) i d f i h b df(x) is an assumed function at each boundary.

Point of action of N, the normal force at the base, is known or assumed [for example at the mid point of base, or vertically below center of gravity of slice]

f(x) is assumed to be a linear function, half sine, li d i t id l d t i t ifi dclipped sine, trapezoidal, or data point specified

Solve for SF, , N, E, b [line action of inter slice forces]

With pore water pressure

Explain failure mechanism during heavy rainfall!!

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With earthquake

With Soil Reinforcements

reinforcement

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Safety Factors of Clay Embankments in Saturated Clays:

FILLCUTCUT

Sudden Drawdown Failure in Dam Upstream Face

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Geostudio – SLOPE 2007

Comprehensive literature:

SLOPE/W 2007 engineering book –by Geoslope International, 2007

Delft Slope Stability Worksheet

Slope.exe

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Revisit Shear Strength Problems?