With rising cases of landslides and slope destabilisation in hill areas where national highways have been constructed, the ministry of road transport and highways is looking at a comprehensive set of matrices to identify slope vulnerabilities and cost-effective remedial measures to reduce the impact of these incidents.
The ministry had formed a six-member technical expert committee across academia, policymakers, and industry to suggest the matrices going forward. It has now sought stakeholder comments on the framework put forward by the panel.
“Expansion of national highways in hill roads having a mountainous/steep terrain involving a lot of hill cutting has resulted in landslides and destabilisation of slopes, which are mitigated and protected using various methodologies suggested in different guidelines,” the ministry said in its circular.
The ministry said it felt the need to have a standardised set of on-site investigations to be done for field engineers for different types of slopes and one for cost-effective protection and mitigation measures.
According to the report, there are also landslides in hill roads built several years ago. There is a need for proper slope stability measures on both hill and valley sides. Such treatments are generally provided during project implementation or subsequently as a reactive measure to landslide.
There are several protection/mitigation measures available for the stability of slopes, such as natural vegetation, rockfall barriers, surface treatments and structural treatments, and others for remedial measures as well.
“However, there is a gap in identifying the type of investigations needed for a particular type of slope and, subsequently, the selection of the type of mitigation measures for that slope. As a result, there is a lack of consistency in the field investigations performed and the mitigation measures used for similar types of slopes, which sometimes result in very high-end structural treatments without proper justification,” the report said.
The report suggests a framework for reconnaissance surveys, topographical mapping, geological investigation, hydrological and meteorological investigations, geophysical investigation, geotechnical investigation, and a number of mitigation measures.
Stakeholders will submit their suggestions within 15 days.
In the past, environmental activists have called for a more rigorous mechanism for sanctioning and approval of road projects in environmentally sensitive areas like hills.
First Published: Jul 25 2024 | 9:07 PM IS