Himalayan Geology, Vol. 38 (2), 2017, pp. 156-170, Printed in India
Geomechanical characterisation of slopes for assessing rockfall hazards in the Upper Yamuna Valley, Northwest Higher Himalaya, India
VIKRAM GUPTA1*, IMLIRENLA JAMIR1,2, VIPIN KUMAR1, MEENAKSHI DEVI1
1Wadia Institute of Himalayan Geology, Dehradun 248001, India
2Nagaland University, Meriema, Nagaland, India
*Email (Corresponding author): vgupta_wihg@yahoo.com
Abstract: The present study encompasses the slope stability analysis along six km long bridle path between Janki Chatti and the Yamunotri shrine, located to the north of Main Central Thrust which consists of rocks of the Higher Himalayan Crystallines mainly comprising quartzite, marble, augen gneiss and garnet bearing mica schist. It has been reported that numerous mass movement activities, mainly rockfall occur in the area and pose serious threat to the lives of people visiting the shrine every year. Therefore, geomechanical characterisation of the slopes for the assessment of rockfall hazards through various rockmass classifications has been carried out. The area is of strategic importance as thousands of pilgrims stroll this path during the pilgrim season that last from May to October every year.
Different geomechanical characterization of slopes has been carried out at 24 locations using RMR, SMR, CSMR, GSI classification along with the kinematic analysis of discontinuities. It has been noted that kinematic analysis of discontinuities gives a conservative estimate of hazard in comparison to different classification of rock mass. It has been established that two locations falls under the category of very high hazards, ten under high hazard and twelve under moderate hazards. These have been correlated with the conditions of rockmass. It has further been noted that different rock mass classifications are in agreement with one another.
Key words: Geomechanical, rockfall, Yamunotri Temple, Higher Himalaya, India
