Home About Us NRDMS Centers Projects Submitted NRDMS 10th Plan
    
  
Related Sites
Home > New Initiatives > Large scale geological
Large scale geological-geotechnical mapping of vulnerable landslide zones along Rishikesh-Kedarnath National highway, Uttarakhand



Himalayas are one of the tectonically active mountain chains of the world. These are highly prone to mass movement due to immature topography, seismic activities, neotectonism, varied hydrological conditions coupled with the high rainfall and complex geology. Transportation, public networks and all socio-economic activities that occur in the areas of Lesser Himalayas are very much dependent on the local road and highway network in this region. Himalayas are undergoing constant rupturing in the thrust belt zone in the Garhwal zone. This has led to triggering of local hazards such as earthquake, landslide and flood, which are interrelated and common in this region. A massive disaster occurred during June, 2013 in Kedarnath due to sudden, heavy rain and cloudburst on Chaurabari Glacier causing flash floods that further aggravated slope instability at different places on the downstream side of the Kedarnath (Fig. 1). For the purpose of economy and safety, the slopes along the national highways in the Himalayan region must be investigated in detail by the geoscientists.



Fig 1: Destruction at Kedarnath locality after the Uttarakhand tragedy of June 2013


Kedarnath town is located in Uttarakhand and has gained importance because of Kedarnath temple (30º73' N and 79º06' E).  

The upper part of Kedarnath is situated in Mandakini Valley of Rudraprayag district. It is glaciated with Chaurabari and Companion glaciers. Kedarnath is located near snow cover in glacial outwash plain area of Himalayan region at the height of approximately 3,583 m above sea level. Rambara village is the nearest place to Kedarnath which was the resting place for devotees, tracking to Kedarnath. According to news agencies, it was reported that after the Kedarnath tragedy whole village is vanished from its place and now there is no sign of any township. The entire area, which housed around 100-150 shops and five hotels, was completely washed away leaving no trace of civilization. The 2013 calamity in Uttarakhand is considered as India’s worst natural disas­ters after the tsunami in December, 2004.


Rudraprayag has already faced eight major natural disasters within last three decades (Table 1). During 1953-1980, 764.48 million people suffered only due to flood and natural disaster.  The problems become more provoked during monsoon period (mid-June to mid-September).


Table 1: Severe disasters, their causes and effects in Himachal Pradesh and Uttarakhand at different time


Type

Date

Month

Year

Affected area

GOLF/ Flash flood

31

July

1991

Mailing, Himachal Pradesh

Landslide

24

February

1993

Jhakri, Himachal Pradesh

Flash Flood

11

August

1997

Tehsil, Himachal Pradesh

Cloudburst

9

June

1997

Chandmari, Sikkim

Extreme rainfall

11-19

August

1998

Rudraprayag, Uttarakhand

Cloudburst/landslide

16

July

2001

Rudraprayag,Uttarakhand

Cloudburst

31

August

2001

Tehri, Uttarakhand

Cloudburst

10

August

2002

Tehri, Uttarakhand

Cloudburst

16

July

2003

Kullu, Himachal Pradesh

Extreme rainfall

17

July

2004

Pasighat, Arunachal Pradesh

Cloudburst

6-8

August

2010

Leh, Ladakh. Jammu and Kashmeer

Cloudburst

18-19

September

2010

Almora Pithoragarh, Uttarakhand

Cloudburst/ Flood

16-18

June

2013

Kedarnath, Uttarakhand

Various reasons are presented for these calamities. Dubey et al.(2008) suggested that more than 200 mm of rainfall in 24 hrs in the moun­tainous terrain could be considered as a cloud burst which can trigger landslides. While Nandargi and Dhar considered rainfall of more than 250 mm in 24 hrs as an extreme event within the Himalayas. Many suggest this event has occurred due to flash floods while others are in favour of a cloud burst. According to the Indian Meteorological Department, rainfall in Uttarakhand during 20th to 26th June 2013 exceeded by 375 percent of than the benchmark rainfall, causing the melting of Chaurabari Glacier at the height of 3800 metres (Fig. 2-3). As a consequence, heavy flood was triggered near Gobindghat,  Kedar Dome, Rudraprayag district in Uttarakhand and the adjoining areas.



Fig 2: Satellite image data showing the condition of glacier around Kedarnath before and after Uttarakhand disaster of June, 2013



Fig. 3: Showing the magnitude of rainfall at different places near Kedarnath during 16th and 17th June 2013


All the 13 districts in Uttarakhand were affected by floods; of these the worst affected four districts are Uttarkashi, Rudraprayag, Chamoli and Pithoragarh districts. According to the gov­ernment officials, more than 1000 people are expected dead with more than 6000 missing and tens of thousands displaced.


In this conceptual note, we propose a special investigation in the affected areas of Uttarakhand from Kedarnath to Srinagar Garhwal (Fig. 4). Due to such a disastrous and alarming problem, the authorities and researchers must come forward and organise a detailed and planned scientific research and analysis. Such an investigation would include a multidisciplinary study of failure prone areas of Uttarakhand and other parts of the Himalayas posing recurrent occurrences of hazards. The multidisciplinary approach will include studies related to remote sensing, environmental sciences, geotechnical engineering, structural geology, geophysical estimations, etc. All these studies will increase the confidence in safety from such disasters in future.



Fig 4: Satellite image showing Srinagar-Garhwal to Kedarnath


By combined investigation through remote sensing, geotechnical engineering, structural studies, stratigraphy and micro-hazard zonation, a potential hazard map can be prepared to demarcate the safe vs. unsafe regions.


High resolution remote sensing data can identify the probable zones of failure. By the reconnaissance survey, target areas can be identified for the detail ground investigation. Any seasonal or continuous change within the glaciers in the vicinity of Uttarakhand can be studied thoroughly from time to time using high resolution time series data. Landslide monitoring studies become more reliable if it they are supplemented by the detailed ground investigation of various geotechnical, geological and structural parameters.


Flooding has reduced the strength of the rocks. Affected slopes along the national highways are not very stable; many landslides can be seen along the roads which obstruct the traffic and causes loss of life and economy (Fig. 4). The affected slopes in this region can be identified by geoscientists and engineers and possible remedies of reinforcement may be suggested. Following pictures show the condition of slopes affected by the Uttarakhand tragedy which needs the proper geotechnical treatment to restore high factor of safety. These slopes need to be analysed for the most appropriate remedy.



Fig 4: Conditions of the hill slopes in the Uttarakhand


Intense folding and faulting and ongoing neotectonic activities within the Himalayan region continuously affect the stability of the slopes. Detailed mapping of the regional geological structures will guide the planners to identify the relatively safe zones for the rehabilitation. Stress and strain analysis can identify the amount and nature of forces acting and deformation within the rock mass. Startigraphic studies are very significant to understand the stratigraphic control over the stability of the whole region. Geophysical surveys of the relatively unstable slopes can provide the health of the rocks at sub-surface which can be stabilized using suitable rock mass reinforcement techniques.


The focus of investigation will be detail geotechnical studies for understanding of health of these slopes. These studies will include various rock mass characterization such as rock mass rating (RMR), slope mass rating (SMR) and landslide susceptibility score (LSS) by which rockmass can be classified into different ranks of stability. Kinematic analysis will be done to investigate the type of failure that may occur and which will also include the method to prevent the rock mass from failure by using suitable reinforcement method. Micro-landslide zonation of whole area using various geological, geotechnical, hydrological parameters can be done which will provide a broader picture of risk. Apart from these conventional techniques we will apply various state-of-the-art 2D and 3D simulation techniques on the slopes. Simulation techniques present a very detail picture of the problem which not only compute the FoS using different techniques but also compute the distribution of stress-strain, displacement etc alongside a pictorial representation of the varied scenarios.


Disasters like floods, landslides, seismicity are causing various environmental threats. Environmental investigation of the affected areas by the Uttarakhand calamity of June, 2013 can be investigated and possible measures can be suggested to reduce the hazardous environmental problem of the region. Many hydroelectric projects are running including large dams like Tehri dam consisting huge reservoir, extensive natural processes like heavy rainfall and cloud burst in the upstream of the reservoir may give rise to more serious hazard and can cause huge damage to the life and economy.
In an outline, the investigation of the highly vulnerable regions surrounding nearly 120 Kms from Srinagar-Garhwal to Kedarnath will be a detailed one consisting of all aspects of stability of the entire stretch. It is emphasised that such studies are inevitable at this stage owing to the high societal relevance of the problem. The 120 Kms stretch would be divided into different patches for focused investigation in each.


Tables for data acquisition and preliminary analysis in the field

Table

Investigations

Training responsibility

Table I

Geological and structural mapping

Dr. V. C. Thakur
Prof. D. C. Srivastava

Table II

Geomorphological and hydrological investigations

Dr. Pradeep Srivastava,
Prof. Y. P. Sundriyal

Table III

Engineering geology, geotechnical investigations, instrumentation

Prof. T. N. Singh,
Prof. Mahendra Singh,
Dr. Rajbal Singh,
Dr.Vikram Gupta

Table IV

Seismic and  SAR investigations

Prof. M. L. Sharma,
Prof. Manoj Arora, 
Dr. J. Das
Dr. R. S. Chaterjee

Table V

RS and GIS

Dr. S. K. Srivastava

Table VI

Spatial analysis and interpretations, report writing

Prof. M. L. Sharma,
Prof. Manoj Arora
Dr. S. K. Srivastava

A four day workshop consisting of training, field and panel discussions have to be organised for all PIs/CO-PIs at one place. All PIs/Co-PIs will get training in all aspects of the project along with field exposures in one of the sectors selected for the project.
The investigation matrix for each patch will consist of information as follows:

  1. A detailed field investigation report consisting of collection of rock samples, water samples, structural, remote sensing data, etc. An inventory of entire data will be created. Critical data will also be plotted in the map of the area.
    1. Detailed structural mapping (line mapping, window mapping, digital imaging) of nearly 120 Kms from Srinagar-Garhwal to Kedarnath can be prepared emphasizing on the structural discontinuities in the field as geological structures have direct control on the stability of the slopes. Stereographic projection can be done to understand the relationship between slope and geological discontinuities, which defines the stability of the slopes. The data of orientation of slope and discontinuities obtained from the field can be plotted on the stereonet and by calculating angle of internal friction we can also determine the type of failure in that rock mass. Structural investigation will also include calculation of stress and strain at different locations within the rock mass.
    2. Rock samples from each location will be collected from various parts of the slope. Lithological variations in each stretch will be identified and mapped. Stress will be given to create lithologs and reconstruction of the origin to metamorphism of these rocks.
    3. The deformation and evolution history of the region is extremely vital for studies on stability of the system in the longer run. Detail structural data consisting of attitude of lithounits, joints, shear/deformation indicators, secondary folding and faults will be collected in the data matrix.
    4. Stratigraphic understanding of these groups of rocks will be important to understand the stratigraphic controls over the stability of the whole area. Geophysical surveys can be conducted to detect the surface and sub-surface changes in rock behavior.
    5. The hydrological status of the areas needs to be studied. Identify all current structures, subsurface utilities, wells, manmade fills, and other surface features. The flow of river channels, the consequences of rise and fall on soil state, regional and local variations in depths of occurrences of water bodies will be studied. Vegetation, topsoil, paving, and other surface coverings will be covered in the study.
    6. Necessary instrumentation will be deployed in the slopes for monitoring the motion on surface and sub-surface of the slopes. Data collected will be analyzed on a regular basis.
    7. Local history of geohazards will be collected based on traces of failures or previous investigations. These may include debris flow, slope failures, subsidence, liquefaction, floods, seismic activities, etc.
  2. Morphometric analysis of drainage basinis the quantitative description and analysis of drainage in an area. Remote sensing and Geographical information system (GIS) techniques will be effectively used in determining the quantitative description of the basin. Morphometric parameters such bifurcation ratio and drainage density determine virtually about the structural distortion in that area. Form Factor will indicate the peak flow of surface water. Similarly the parameters investigated during the morphometric analysis will provide several vital informations about the area. Drainage in the area can be marked using satellite imagery or by the aerial photographs. Whole area can be divided in to sub-watersheds and following data can be calculated to determine the surface and groundwater conditions in the area.

 

  1. High resolution remote sensing information for the region will be collected and monitored over time to identify variations in slope conditions. Data for all three seasons will be collected to identify any change. The data from earlier times will be compared with the present ones, particularly in terms of occurrence and distribution of vegetation, movement of water containments, lithology, etc. Collection and interpretation of real term data will be done using advanced remote sensing techniques such as Light Detection and Ranging [LiDAR]. Typical morphological changes in slope profiles using stereomaps and the susceptibility will be understood using the remote sensing data. In short, the four way study of risk zones mapping will be carried in aerial photos, satellite interpretation, ground surveys and comparison with the historical data. A spatial distribution of minor movements of points/lines/plane can be identified and acted upon accordingly.
  2. Geomechanical characterization will form the basis of such studies for monitoring the health of road cut and natural slopes along the stretch. The collected rock samples will be carried and tested in the laboratory.
    1. Complete geomechanical profile of the rocks will be made and data sheet consisting of all properties will be prepared. UCS, seismic velocities, density, porosity, permeability, shear strength, cohesion, angle of internal friction, etc. will be determined for the rocks collected during different periods of the year. A similar study will be done for the soil samples collected from areas dominated by soil slopes.
    2. The study of samples will be extended to the simulated in-situ conditions in the laboratory through novel experimental set up. Mode for injection of fluids (as seepage/flow in monsoons) in rock samples during loading will be provided for more realistic estimations. Acoustic emission technique of monitoring the generation and propagation of fractures during loading
  3. Multi parameter rock mass characterization of the whole 120 patch from Srinagar-Garhwal to Kedarnath can be conducted, which will include the detailed field investigation and laboratory tests. Various classification schemes such as rock mass structure rating (RSR), rock mass rating  (Geomechanics classification/RMR), Rock quality tunneling index (Q), Geological strength index (GSI) and Slope mass rating (SMR) can be done for the slopes seems probable to failure. Detail analysis of the rockfall phenomena in each zone will be studied in details. On the basis of the grade the rock mass can be stabilize using various reinforcement techniques such as grouting, rock bolting, guniting, cable anchorage etc. for the purpose of safety.

Some important parameters will be reported for the detailed description of the rock mass. 

  1. Apart from the hard rock study soil cover will also be investigated by investigation of soil properties such as permeability, settlement, capillarity, bulk density, dry density, relative density, moisture content, void ratio, degree of saturation, porosity etc. and grading curve of soil can also be calculated that will also very significant for the geotechnical studies of the soil. For further detailed investigation of the soil limits of consistency can be calculated for the cohesive soil using Casagrande apparatus and cone penetrometer test. Ultimately the soil can be classified for the in engineering purposes using various schemes of classification such as textural classification, Unified soil classification, ASHTO soil classification (American association of state highway and transportation officials).
  1. To have a qualitative identification of a rock mass classification can also be done on the basis of degree of weathering. Rock mass of Srinagar-Garhwal to Kedarnath can be investigated using classification based on degree of weathering of rock mass.

 

  1. Weathering is an important factor which controls the stability of the slopes, degree of weathering depends upon several factors. Degree of weathering can be investigated using slake durability index test for weathering.
  2. Slope investigation using conventional and advanced methods will be done for detail insight into the status of the slopes. Kinematic analysis based on the structural orientation of the joints and litho-units will be done. Kinematic analysis of slopes can define the stability of the slopes with the pictorial representation of the data. The pertinent geomechanical properties of the rocks will be used to create a two-dimensional model of the slopes. Three-dimensional models will provide a more suitable picture of the inside of the slopes. Such studies will reveal not only the factor of safety of the slopes but also help determine the stress-strain of slopes, displacement and velocity vectors and possible deformation due to changes in properties of rocks in pre-, post- and during monsoons. The seismic activities in the area influence of movement of men and machinery on the stability of slopes will be incorporated in these models. Micro-landslide zonation map of the entire area with the help of these results will be created, while incorporating the hydrological and geological parameters.
  3. The report for each of the patch containing detail studies will be compiled in three forms: a tabular depiction of results for easy comparison, zonation maps for each category highlighting the variations in these parameters, detailed report of the area. Remedial measures based on the studies will be suggested. Pilot tests for implementation of remedial measures will also be conducted at selected locations. Development of technology will be a part of this study. Based on image analysis techniques, new sensors will be development for detection of rock movements. Rock frictional apparatus will also be developed to characterize rock motions along surfaces that may either create locking of failures or enhance conditions for failures. Retaining systems, rockeries and foundation supports with specific design and construction recommendations will be suggested wherever necessary. A final report consisting of detailed investigation, monitoring and suggested remedies will be compiled at the end of the study.

Objectives

  1. Geological/geotechnical mapping on 1:10000 scale with critical zones on scale not less than 1:1000
  2. Geometric, kinematic and dynamic analysis of the field observations
  3. Determination of constitutive parameters for slope stability analysis
  4. Preparation of user friendly data base in GIS framework
  5. Modelling of physical process, its simulation and prediction
  6. Probabilistic approach for risk assessment
  7. Remedial measures and societal aspects

Area of Study and organization associated


Traverse

Sectors

Organisation

Rishikesh to Devprayag – 70 km

Sector I

IITR/IPU

Devprayag to Srinagar  - 35 km

Sector II

IITB/PGCP

Srinagar to Rudraprayag – 34 km

Sector III

CRRI/PU

Rudraprayag to Sonprayag – 45 km

Sector IV

WIHG/KU

Sonprayag to Kedarnath -  23 km

Sector V

WIHG/HNB

 

Organisation wise probable principal investigators/investigators
IIT Roorkee


PI

CO PI

Area of specialization

Prof. D. C. Srivastava

 

Structural Geology  

Prof. M. L. Sharma

Dr. J. Das

Geophysical and SAR

Prof. Mahendra Singh

 

Geotechnical investigations

GGSIP


PI

CO PI

Area of specialization

Dr Varun Joshi

Dr Kiranmay Sarma

Geological mapping

IIT Bombay


Prof. T. N. Singh

Dr Kumar Hemant

Geological/Geotechnical and modelling

PGCP


Dr. R. A. Singh

 

Geological mapping

CRRI


Dr. Pankaj Gupta

Sh. Kanwar Singh

Geological and geotechnical investigations

Panjab University/PEC


Dr. Mahesh Thakur

Prof. L. N Sharma

Geological and geotechnical investigations

WIHG


Dr. Pradeep Srivastava

Dr. Perumal

Geological 

Dr. Vikram Gupta

Dr. Venkatesh, NGF

Geotechnical investigations

HNB


 Dr. Y. P. Sundriyal

 Dr. S. P. Sati

Structural Geological investigations

 

 

Geotechnical*

KU


Dr. P. D. Pant

 Prof. R. C. Joshi

Structural Geological investigations

 

 

Geotechnical**

*  WIHG will take care of this component
** IITB will take care of this component

IIRS


Dr. S. K. Srivastava

 

Compilation and spatial analysis of data acquired in GIS format
Final end user product

 

Experts/PIs associated
Prof. T. N. Singh, IITB, Program Coordinator

  1. Dr. V. C. Thakur, Geological and Geomorphological  investigations
  2. Dr. Rajbal Singh, CSMRS, Rock Mechanics and Instrumentation
  3. Prof. Mahendra Singh, IITR, Geotechnical investigations
  4. Prof. M. L. Sharma, IITR, Seismic, Geophysical and SAR interferometry
  5. Prof. Manoj Arora, PEC, SAR and Geo-informatics
  6. Prof. T. N. Singh, Dr. Rajbal Singh, Prof. D. C Srivastava and Dr. Mahendra Singh, Technical Training on data acquisition
  7. Prof. Manoj Arora, Prof. M. L. Sharma, Dr. S. K. Srivastava, GIS frame work for data set
  8. Prof. Mahendra Singh, Prof. T. N. Singh, Stability analysis.

Important Tasks and landmark

  1. Primary Maps and Data Set generation

Task IGeological and Structural mapping
Task IIGeomorphological and engineering geological mapping
Task IIIGeotechnical parameters determination
Task IVGeophysical data acquisition
Task VDemographic and built environment typology

  1. Analyses

Task VISlope stability analysis
Task VIISeismic vulnerability analysis
Task VIIISpatial analysis for vulnerability zonation
Task IXRisk assessment

  1. Modelling and Simulation

Task XModelling of physical process
Task XISimulation and validation of physical process

  1.  Recommendation

Tasks XIIRecommendations for remedial measures for disaster prevention

Base map of the study area
Important Note: Data has to be provided in vector format and not raster format in form of shape files.(.shp)

 

Table 1

Structural data obtained from the field can be reported in tabulated form as:


Name of  PI:

Date:

Locality:

Toposheet No.

Coordinate:

Altitude:

Lithology:

Slide History (Date/type/material)

Traverse no:

Length of traverse:

Distance between two traverse:

Lithology/Stratigraphy

Top soil/ vegetation

Hydrological status

Natural / Man-made Structures

Major geological structures

Cleavage

Photograph No./Hand sketch

Lineation

Foliation

Faults

Fold

Shear Zones

Thickness of strata/ filling material

Other structures if any

 

Photograph No./  Hand sketch

Slope/ Discontinuities

 

Strike

Dip

Slope face

 

 

Bedding

 

 

Joint (J1)

 

 

Joint (J2)

 

 

Remarks with structural map

 

 

 

 

 

 

 

 

 

 

 

 

 

Table 2 Engineering geological field parameter


Engineering properties of rocks

Details

Location

 

Lithology

 

Coordinates

 

Slide type (if rockfall, then possible source, height and size of blocks)

 

Type of movement

 

Material involved

 

Dimension of slides/ Geomorphological details

 

Geometry of slope

 

Slope/ Discontinuities

 

Strike

Dip

Slope face

 

 

Bedding

 

 

Joint (J1)

 

 

Joint (J2)

 

 

Discontinuities parameter

No of joints

Joint compressive strength

Joint persistence

Joint roughness

Joint spacing

Joint Aperture

Infilling material

Water condition

Degree of weathering

Scanline mapping (at least 3-4m)

Location (Distance, End point)

Structure (Type, Dip attitude, Rock, Plan)

Geometry (Above and below, trace length)

Remarks

Estimated SMR/ GSI on the site (as per standard)

 

Damage and Risk due to landslide

 

Concluding Remarks with photographs and sketches, map

 

Table 3 Engineering properties of soil


Location

 

 

Type of sample collected

 

 

Coordinates

 

 

Geomechanical parameters of soil

Grain size

 

 

Grain shape

 

 

Porosity

 

 

Permeability

 

 

Soil moisture

 

 

Compressive strength

 

 

Shear strength parameters

 

 

Bearing capacity of soil

 

 

Residual stress

 

 

Specific gravity

 

 

Density

 

 

Sensitivity of clay

 

 

Atterberg limits

 

 

Void ratio

 

 

Swelling capacity

 

 

Table 4 Engineering properties of rock


Location

 

 

Type of sample collected

 

 

Coordinates

 

 

Geomechanical parameters of rock

Density

 

 

Water Absorption

 

 

Porosity

 

 

Slake durability index

 

 

Moisture content

 

 

Compressive strength (Dry/weight)

 

 

Point load index

 

 

Tensile Strength

 

 

Shear strength parameters

 

 

Elastic constants (with stress strain curves)

 

 

P and S wave velocities

 

 

Post peak strengths (if possible)

 

 

Table 5 Miscellaneous parameters


Anticipated extent of damage

 

 

Anticipated cause of landslide

 

 

Water table conditions

 

 

Agricultural/ forest land

 

 

Disruption of communication network/infrastructures

 

 

Deaths/casualty

 

 

Presence of pre-existing landslides

 

 

Past snowfall/ rainfall/ temperature variation etc. data

 

 

Nearby anthropogenic activities

 

 

Previous stability measures (if any)

 

 

Other important and relevant data sets