Forensic Analysis of Landslides: Sardar Vallabhbhai National Institute of Technology, Surat
Forensic Analysis of Landslides: Sardar Vallabhbhai National Institute of Technology, Surat
Forensic Analysis of Landslides: Sardar Vallabhbhai National Institute of Technology, Surat
Presented By :
P17SM001
Sayali S. Gosavi
Guided By :
Dr. Satyajit Patel
1
Objectives
2
Introduction
3
Causes Of Landslide
• Landslides occur when the slope changes from a stable to an
unstable condition.
• Weakening of a slope through saturation by snow melting, glaciers melting or heavy rain
• Volcanic eruptions
5
Anthropogenic Causes
Deforestation, cultivation and construction, which destabilize the already fragile slopes.
Blasting
Earthwork which alters the shape of a slope, or which imposes new loads on an existing
slope
In shallow soils, the removal of deep-rooted vegetation that binds colluvium to bedrock
Construction, agricultural activities which change the amount of water infiltrating the soil.
6
Factors Affecting Landslide Classification
1) Type of movement
6) Geological conditions
2) Involved material
7) Morphological characteristics
3) Activity
8) Geographical location
4) Movement velocity
9) Topographical criteria
5) The age of the movement
10) Type of climate
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Lateral Spreading Debris Flow Velocity Comparison Of Mass Movement
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Effects Of Landslides
11
Forensic Analysis Of Landslides
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Steps Involved In Analysis
1) Preliminary work -
Study of archival materials
Terrain reconnaissance
Talk to local people
Conceptual engineering, geological model
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2) Landslide investigation -
Engineering geological mapping
Longitudinal and cross sections
Boreholes, trial pits, rock and soil sampling, field tests,
geophysics
Laboratory tests
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3) Finding the depth of rupture surface-
4) Monitoring -
Monitoring of deformation
Monitoring of hydro-geological features, GWL and pore
pressure fluctuation, spring yield
Measurement of stress
Indirect methods -geophysics
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5) Methods of prognosis -
Spatial prognosis
Prognosis of mechanisms and dimension of failure
Time prognosis
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Methodologies Of Slope Stability Analysis
1. Bishop’s Method of Slices- It is used when the slope consists of different
soil layers with varying c and ɸ values.
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2. Back Analysis of The Failed Slope –
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Generic causes and
observed technical
errors of MSE failure
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Summary and Conclusions
• In today’s litigious society the failure of a geotechnical engineering project brings
together the engineering and legal professions to resolve the conflict of responsibility
for the failure.
• Rainfall events have been the major triggering factors of landslides in many areas.
• In most of the cases initial steps are almost same in the analysis. The main aim is to find
the cause of instability of slopes. There are various methods available for stability
analysis of slopes. Based on severity of damage caused by landslides, analysis is to be
performed by selecting a proper method. 23
Summary and Conclusions
• The statistical approach has been used extensively for decades in forensic studies,
because it can be used to summarize or interpret sophisticated information and is the
means of communicating the results of observations to engineers.
24
References
• Souza L, Naik A, Mhaddolkar P, Naik N. Case study and forensic investigation of landslide at Mardol in
Goa.
• Cruden, D. M., & Varnes, D. J. (1996). Landslides investigation and mitigation, transportation research
board. Landslide types and process, National Research Council, National Academy Press, Special
Report, 247, 36-75.
• Hungr O., Evans, S. G., & Hutchinson, I. (2001). A Review of the Classification of Landslides of the Flow
Type. Environmental & Engineering Geoscience, 7(3), 221-238.
• Popescu, M. E. (2007). Risk assessment and treatment in slope stability forensic engineering. In Forensic
Engineering (2006) (pp. 141-153).
• Popescu, M. E., & Sasahara, K. (2009). Engineering measures for landslide disaster mitigation.
In Landslides–Disaster Risk Reduction (pp. 609-631). Springer, Berlin, Heidelberg.
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References
• Lucia, P. C. (2012). The practice of forensic engineering. In Geotechnical Engineering State of the Art
and Practice: Keynote Lectures from GeoCongress 2012 (pp. 765-785).
• Wu, J. Y., & Chou, N. N. (2012). Forensic studies of geosynthetic reinforced structure failures. Journal
of Performance of Constructed Facilities, 27(5), 604-613.
• Stead, D. O. U. G., & Eberhardt, E. R. I. K. (2013). Understanding the mechanics of large landslides. Ital.
J. Eng. Geol. Environ. Book Ser, 6, 85-112.
• Ering, P., Kulkarni, R., Kolekar, Y., Dasaka, S. M., & Babu, G. S. (2015). Forensic analysis of Malin
landslide in India. In IOP Conference Series: Earth and Environmental Science (Vol. 26, No. 1, p.
012040). IOP Publishing.
• Igwe, O., Effiong, B. A., Iweanya, M. R., & Andrew, O. I. (2015). Landslide investigation of Ikwette,
Obudu Local Government Area of Cross River State, Nigeria. IOSR J Appl Geol Geophy (IOSR-
JAGG), 3(3), 1-12. 26
References
• Lacasse, S. (2016). Forensic geotechnical engineering theory and practice. In Forensic
Geotechnical Engineering (pp. 17-37). Springer, New Delhi.
• Abidin, M. H. Z., Madun, A., Tajudin, S. A. A., & Ishak, M. F. (2017). Forensic assessment on near
surface landslide using electrical resistivity imaging (ERI) at Kenyir Lake Area in Terengganu,
Malaysia. Procedia Engineering, 171, 434-444.
• Spreafico, M. C., Wolter, A., Picotti, V., Borgatti, L., Mangeney, A., & Ghirotti, M. (2018). Forensic
investigations of the Cima Salti Landslide, northern Italy, using runout
simulations. Geomorphology
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