Chandrasekaran S-S

Department of Structural and Geotechical Engineering

School of Civil Engineering

Vellore Campus

Senthil Kumar V

Department of Chemistry

School of Advanced Sciences

V. B. Maji

Vellore Institute of Technology (VIT) is a private university located in&nbsp;Tamil Nadu, India. Founded in 1984, as Vellore Engineering College, the institution offers 20 undergraduate, 34 postgraduate, four integrated and four research programs. It has campuses in Vellore, Amravati, Bhopal and Chennai.

VIT is one of the top ranked private universities in India according to NIRF, THE and QS Rankings.&nbsp;Govt. of India has recognized&nbsp;VIT, Vellore as an&nbsp;Institution of Eminence. This has allowed VIT to take independent quality initiatives and move up in world ranking.

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VIT University

Landslides in Nilgiris: Causal Factors and Remedial Measures

Developments in Geotechnical Engineering Geotechnical Design and Practice

Landslides are frequently occurring natural hazards in Nilgiris district of Tamil Nadu, India, particularly during monsoon season. The present study describes the geotechnical characterization and analysis of rainfall-induced landslide that occurred at Marappalam location of Nilgiris district on November 10, 2009. The detailed investigation comprises mapping of landslide, topographical survey, field and laboratory investigations, characterization of soil and rock, and numerical analysis. Field study comprises borehole and geophysical investigations. Detailed laboratory investigation was performed to identify index and engineering properties of soil and rock. Based on the results obtained from field and laboratory investigations, the generalized subsoil profile of Marappalam slope has been plotted. The investigations revealed that loose and soft soil layer with low permeability and plasticity interspersed with boulders could be the main source of debris flow. Scanning electron microscopic analysis and x-ray diffraction analysis were performed to study the influence of weathering on slope failure. Failure mechanism of Marappalam 2009 landslide was identified from the numerical analysis performed using landslide simulation program LS-RAPID. The analysis revealed that the 5-day antecedent rainfall (303 mm) and intense rainfall on 10th November 2009 (405 mm) saturate the slope due to infiltration of rainwater. This leads to a decrease in the matric suction and subsequent development of positive pore water pressure, which in turn reduces the shear resistance of the soil along with shear displacement, and resulted in a progressive failure. © 2017, Springer-Verlag Berlin Heidelberg.

Landslides

Geotechnical characterization and analysis of rainfall—induced 2009 landslide at Marappalam area of Nilgiris district, Tamil Nadu state, India

The Nilgiris district in the Tamilnadu state of India is frequented by many landslides in the recent past. Though many of these landslides are rainfall-induced, there is a need to evaluate the potential of earthquake-induced landslides considering seismicity of the region. In this paper, deterministic seismic hazard of Nilgiris is carried out by considering a study area of 350 km radius around Nilgiris. Seismotectonic map of the Nilgiris, showing the details of faults and past earthquakes, is prepared. The peak ground acceleration (PGA) at bed rock level and response spectrum are evaluated. The potential sources for Nilgiris are Moyar and Bhavani shears. The PGA at bed rock level is 0.156 g corresponding to maximum considered earthquake 6.8. Ground response analysis for seven sites, in the Nilgiris, is carried out by one-dimensional equivalent linear method using SHAKE 2000 program after considering the effect of topography. PGA of surface motion got amplified to 0.64 g in Coonoor site and 0.44 g in Ooty site compared to 0.39 g of the input motion. The bracketed duration of time history of surface acceleration has increased to 20 s in Coonoor site and 18 s in Ooty site compared to that of 8 s of input motion. Results from seismic displacement analysis using Newmark’s method revealed that out of seven sites investigated, five sites have moderate seismic landslide hazard and two sites (Coonoor and Ooty) have high hazard. © 2015, Springer Science+Business Media Dordrecht.

Natural Hazards

Evaluation of seismic hazard and potential of earthquake-induced landslides of the Nilgiris, India

India is among the top ten countries with the highest percentage of landslide fatalities for the past few years. Intense rainfall during the 2009 monsoon in the hilly district of Nilgiris, in the state of Tamilnadu in India, triggered landslides at more than 300 locations which affected road and rail traffic, destroyed buildings, caused the death of more than 40 people and left hundreds homeless. In this paper, three case histories from Nilgiris district are investigated: the slope failure of a railway track at Aravankadu, failure of retaining walls supporting buildings at Coonoor, failure of the slope and retaining wall along national highway (NH67) at Chinnabikatty. Laboratory investigations are carried out on soil samples collected at these sites. Soils at all the three locations have high fine content and low values of coefficient of permeability. Finite element analyses of all the three case histories were carried out using PLAXIS2D software in order to understand the failure mechanism and contributing factors. Slope stability analysis using strength reduction technique is carried out for the slope at Aravankadu to determine the critical slip surface and factor of safety. Results reveal that the increase in pore pressures led to a reduction in shear strength of the soil and consequently resulted in progressive failure of slope at Aravankadu site. Displacement analysis is carried out for Coonoor and Chinnabikatty sites. The results show that combined effect of surcharge load of building and high pore pressure led to intense shearing behind the retaining walls at Coonoor site. Results indicate occurrence of large displacements along the face and at toe of the slope at Chinnabikatty site. © 2012 Springer Science+Business Media Dordrecht.

Investigation on infrastructural damages by rainfall-induced landslides during November 2009 in Nilgiris, India

Procedia Engineering

Effect of Area Development on the Stability of Cut Slopes

Landslide Science and Practice

Damages to Transport Facilities by Rainfall Induced Landslides During November 2009 in Nilgiris, India

Journal	Data powered by TypesetDevelopments in Geotechnical Engineering Geotechnical Design and Practice
Publisher	Data powered by TypesetSpringer Singapore
ISSN	2364-5156
Open Access	0