Geological Mapping, Geo-Technical Investigation of Ramche Landslide Rasuwa, Central Nepal
Abstract
The study area lies in the Kuncha Formation of the Lower Nawakot group, Central Nepal. The rock type is inter-bedded of metasandstone and phyllite with three set of joints in metasandstone. The area is covered by the unconsolidation colluvium soil with huge rock boulder. In the toe and middle part of the main drainage there are rock exposures. Highly shearing rock exposure and boulder observed on both side, the shearing evidence are silicon slide and highly folded quartz vein.
In the study area, landslide first triggered in 1983 and reactivated from August 2003. This landslide has tentatively 0.5 km2 area cover. The dimension of the landslide is maximum length 1.2 km, maximum width 0.9 km and thickness 20-30 m. The surrounding area covered by cultivation land, settlement and forest. The motor road passes across from the middle part of landslide. The drainage management system is poor, infiltration rate of soil is high and its support from the excavation of road. Then increase the poor water pressure and reduced the soil strength due to the pore water pressure with the artificial load also include i.e. load and vibration of vehicle. By the flashflood and unmanaged drainage system, the gully erosion and toe cutting rate is high. In the toe section, the colluvium was washout, and then the shear strength is decrease and the vertical load was increase and after then the surface was starting to creeping or displacing towards down. With reference to the Google earth image, the inclined displacement distance science 2008 to 2015 was 86 m. The creep started from 2008, at that time it was continuous. There were three road track, two track was old and one is new constructed, all these track moving towards down. Agriculture land and settlement was completely destroyed and remaining land was changed to barrel land with various cracks. There are many spring sources, all of the sources water is infiltrate from the colluvium and is playing the role of erosion of surface and subsurface.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFMIN33B0863B
- Keywords:
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- 0240 Public health;
- GEOHEALTHDE: 1630 Impacts of global change;
- GLOBAL CHANGEDE: 1980 Spatial analysis and representation;
- INFORMATICSDE: 4330 Vulnerability;
- NATURAL HAZARDS