Location: KapKot Village in Bageshwar, Uttarakhand
Brief of the Problem: Destabilization of the slope material
The geological profile of this region faces serious slope stability related problems that are mainly attributed to an active and diverse tectonic setting, high rates of weathering, excessive rainfall, erosion vulnerability, and steep slope cuttings. Kapkot Formation is dominantly represented by rocks of the calcareous facies together with rocks of the argillaceous facies.
Moreover, many anthropogenic activities such as uncontrolled/ un-engineered blasting at the time of road widening also led to slope destabilization. These roadside slopes were needed to be protected so as to avoid the loss of lives, blockage of traffic movement. These landslides occur most frequently as shallow and localized slope failures in roadside cuttings. The majority of landslides result in temporary partial or complete blockages to short sections of the road. These failures can give rise to several hours of delay to traffic and also require ongoing investment in debris clearance, repairs to walls and roadside drains and road pavement.
Engineered Solution: Mitigation Measure for Slope Stabilization
The project was under the scheme of the Uttarakhand Disaster Recovery Initiative and was funded by the Asian Development Bank. The main mitigation measures were to provide slope stabilization of 800 m stretch length for a height varying from 40 to 60 meters. We used High Tensile Galvanized Wire Mesh with Rolled cable Wesh and Anchoring system up to a depth of 7 Mtrs. In some areas hydroseeding was also required to increase the germination of plants.
The flow of the river was very high which created a major scouring issue in the particular region. To deal with this issue, the use of a gabion wall and concrete cladding wall was proposed by the consultant.
A few other things were also required such as a one km drain and culverts for the discharge of high rainfall water.
Difficulties faced during execution:
The detailed project report was prepared by THDC. By the time tender floated, the condition of the location drastically changed due to climate and weather conditions, and a new design was required for the work to take place. Initially we tried to proceed with their original design but after a series of failures we requested the client for the modification of the design and that is when the new design was created.
Reconnaissance geological-geotechnical assessment was made by a team of civil engineers and geologists from THDC. Data collection was done and recorded in a data sheet based on the assessment of site conditions. Analysis of geological slope profile was evaluated and accordingly based on the depth of failure surface; a revised design was issued by THDC.
A system of SDA (self-drilling anchor) having a 38mm diameter was opted in the new design to resist the driving loads and slope movement. In order to prevent the detachment of lose rocks/boulders; High-performance netting and Rolled cable net were used throughout the unstable stretch of 800m along with SDAs.
Galvanized Spike Plate was placed over the Self drilled anchor and connected using Nuts. Spike plate increases the area of contact and makes an intact contact between wire mesh and underlying slope material.
The time allotted for the completion of the project was just six months. In addition to it, the location of the awarded project was in a distant isolated zone, disconnected from basic amenities. The location was at such distance that the machinery/equipment/spares had to be carried to the worksite through hill road which was 200 Kms. away from the nearest point at “Haldwani”
Apart from the site constraints issue, heavy monsoon climate created lots of hindrances for ongoing works. Lose overburden/ debris tends to move due to lubrication generated by repetitive rain events, which delayed the progress.
Overcoming all the challenges, we completed the project within the allotted time of six months. We effectively planned, managed, and streamlined the project in a proper engineered manner to protect the unstable slope profile continuing along the highway. Geo Spar’s mission to provide fast and efficient services with lasting solutions was achieved.
We would like to appreciate Mr. Rahul Kumar (AVP Mechanical) and Mr. Pankaj Bansal (GM) as they handled the entire project and it was because of their hard work we were able to complete the project on time and with efficiency.