We presented the mitigation systems adopted for the Lambagarh landslide and the Mumbai Pune Expressway rockfall events near the Khandala and Adoshi tunnel portals
The conference “Tunneling in Himalayan Geology” was organized by Northern Railway in association with the Central Board of Irrigation and Power (CBIP) and the Tunneling Association of India (TAI) in Jammu on October 11th-13th. We were shared our knowledge and expertise with a technical presentation on advanced landslide and rockfall mitigation systems, as implemented in our two challenging projects to secure the sites of the Lambagarh landslide and of two important rockfall events along the Mumbai Pune Expressway.
Landslides and rockfalls have always been considered part of the Himalaya’s natural developmental process, due to its geological setup, narrow and deep gorges, meandering rivers, snow clad bodies, climatic diversities, sudden and heavy downpour including cloud-bursts, flash floods, earthquakes etc. However, rare natural incidences have significantly increased in the last few decades due to rapid population growth. As human interaction with nature increased, vulnerability of the land to such processes has also increased, resulting in recurring landslide and rockfall events, endangering human lives, properties and infrastructures.
Our first session on “Sustainable Landslide Mitigation Measures” mainly focused on how man-made infrastructures and underground excavations can trigger landslides in the Himalayan regions and set criteria to select the most suitable landslide and rockfall mitigation systems.
Landslides show a great variability in their nature. Slope failures can vary from surficial instability to deep seated failures. Hence, it is important to judiciously select one or a combination of mitigation techniques based on site specific conditions. Various factors such as flexibility, ability to blend with the environment, balancing the cut and fill, carbon footprint etc. should be considered along with the cost effectiveness of the system.
In this regard, we presented our case history on the challenging Lambagarh landslide, on the road to the Badrinath shrine, Uttarakhand state, with river Alakanandha flowing at its toe. This is a chronic landslide site, whose latest occurrence dates back to the major cloud-burst of June 2013, with a massive landslide blocking the flow of the river and causing destruction of the road. For this project, we proposed a combined mitigation system whose construction is currently ongoing.
During our second session “Construction of Rockfall Mitigation Measures Above and Near Tunnel Portals Along the Hill Road”, we presented another case history on the several landslide/rockfall events occurred near the Khandala and Adoshi tunnel portals on the Mumbai Pune Expressway. This is India’s first six-lane concrete, high-speed, access controlled expressway. From June to August 2015, during monsoon season, a series of landslide/rockfall events caused casualties and severe traffic disruptions. Here again a thorough investigation was carried out to identify the most appropriate mitigation systems based on site specific conditions.
A combination of rock scaling, sub-surface drainage system, rock slope stabilization systems such as rock nailing and our secured drapery systems Steelgrid MO and/or high energy absorption (HEA) panels was used at the Khandala tunnel, Pune side portal, while the addition of our dynamic rockfall barriers was also necessary at the Adoshi tunnel, Pune side location.
These mitigation works were successfully completed in December 2016 and survived the following monsoon season without any reported rockfall accidents. For more detailed information, you can read the full paper here.
This paper was also published in the technical magazine “HIMPRABHAT Volume IX” of the Udhampur Srinagar Baramulla Rail Link (USBRL), project of the Northern Railway, which was released on the occasion of the conference.
We were thrilled by the response to our presentation. Conference delegates from various renowned organizations like TAI, CBIP, IRCONS, KRCL, CMFRI, among the others, showed strong interest and proactively participated in an interactive final session, also sharing their geotechnical engineering experiences. The interest continued at our booth, where we were showcasing our advanced landslide and rockfall mitigation systems.
For more information, please contact us.