Slope Stability Analysis of the Mai Khola Rockslide, Ilam District, Eastern Nepal

  • D. Chamlagain Department of Geology, Tri-Chandra Campus, Tribhuvan University, Kathmandu
  • V. Dangol

Abstract

The Mai Khola rockslide is a combination of plane failure and wedge failure along the dip slope in moderately weathered schistose gneiss, and highly fractured quartzite.The total volume of slid material is about 37,500 n3.The major triggering factors for rockslide appear to be discontinuities of rock mass and their relation to natural hill slope, which gave the unique combination during sliding, along with other associated factors. The other causative factors responsible to the rockslide are topographic stress, high slope gradient, joint water pressure and river under-cutting at the toe side. The rock masses within the rockslides are graded as crushscattered to massive. The obtained UCS values classified rock as moderately weak rock to strong rock.The factor of safety (Fs) for the rockslide is 0.73, which indicates that the rockslide is still unstable.