Himalayan Geology, Vol. 40 (1), 2019, pp. 67-77, Printed in India

Slope stability analyses using classification systems and numerical methods: case study from Lower Dir, Khyber Pakhtunkhwa, Pakistan

MIAN SOHAIL AKRAM, MUHAMMAD ZEESHAN*, KAMRAN MIRZA, LUQMAN AHMED, AISHA NOOR, MUHAMMAD ALI

Institute of Geology, University of the Punjab, Lahore, Pakistan

*Email (Corresponding author): muhammadzeeshanpak@gmail.com

Abstract: The present study is to investigate the main factors of slope instability along power house of a small hydropower in Lower Dir, Khyber Pakhtunkhwa, Pakistan. The stability of collapsed slope in the study area highlights a risk of failure for adjoining slopes of a powerhouse. Therefore, slope stability analysis is carried out to investigate the mechanism of failure and to provide remedial measures. Initially, empirical methods; rock mass rating (RMR) and slope mass rating (SMR) were used to characterize the slope and to determine the mode of failures, respectively. Kinematic analysis depicted that intersection line of joint and foliation causes instability by producing a wedge failure. The support is recommended for an unstable slope by using empirical approaches that has been validated and optimized through a limit equilibrium analysis. The analyses suggest that an additional support of 6-10 m bolts with end to end 2 m spacing between the initially installed bolts of 4 m length and a 2 m end to end spacing is required.

Key words: Slope stability, Rock mass rating (RMR), Slope mass rating (SMR), Numerical analysis, Failure mechanism, Optimization of support.67