ASSESSMENT OF A TYPICAL LANDSLIDE IN UTTARAKHAND AND MITIGATION SOLUTIONS

Abstract

we know landslide is a natural phenomenon as well as extremely catastrophic natural hazard. It has a potential to damage any natural landscape, road, railway track, human life, and property. India has many landslide prone states wherein with each passing day, an increase in the population of the country has become a concern for landslide. A larger part of Uttarakhand is already affected by the landslide. This makes it compulsory for us to have a proactive approach for the prevention from landslide rather than waiting for a disaster to occur (NDMA, 2009) The Lakhwar Dam Top Landslide is located at a distance 70km from Dehradun on Dehradun-Yamnotri highway (NH-123) junction with Vikasnagar-Kalsi-Barkot in the district Dehradun, Uttarakhand, India. On the basis of field study survey, the slope has been categorized into two parts. These two categorised slopes were studied and it was found that one of them is potential rock slide and the second is potential debris slide which have been under consideration for detailed investigation. The site is visited during monsoon and after monsoon season. The available predominant materials at the site are soil and rock where soil type is well graded silty gravel and rock type is Phyllite and Sandstone. To quantify the susceptibility of landslide, the Central Building Research Institute (CBRI), Roorkee uses Landslide Susceptibility Score (LSS), while Bureau of Indian Standards (BIS) for uses Landslide Hazard Evaluation Factor (LHEF). Once the problem of landslide is quantified, various civil engineering measures can be suggested which can vary from spot bolting to pattern bolting to erection of retaining wall and even modification of slope. For long-term remediation of Lakhwar Dam Top Landslide, a slope stability analysis and Geotechnical studies were carried out to evaluate suitable mitigation measures. Soil nailing with short creating, Slope Modification with retaining structure, and Drainage Measure etc. are predominantly set of remedial measures designed and suggested to improve the slope and national highway.