Landslides, rock fall and avalanche risk assessment of various landslide types along the railway line between Stjørdal and Steinkjer. Includes, for example, rockfall risk, quick clay slide risk and precipitation-induced landslide, focusing on capacity of subdrains and culverts.

Under commission from the Norwegian National Rail Administration, NGI has carried out a detailed assessment of landslide, rock fall and avalanche risk from side terrain along the Trønder Line between Stjørdal and Steinkjer.

Challenge

Assess different types of landslide, rock fall and avalanche risk against each other so that the sections of line with the highest landslide, rock fall and avalanche risk are prioritised with regard to the implementation of safety measures.

Method

For earthslides, preliminary GIS calculations were taken using a new method developed by NGI. Based on the results of these calculations, inspections were carried out on identified sections of line. For culverts, the calculations of dimensioned water flow were assessed against the capacity estimated during the inspection. In respect of quick clay, ground surveys, ERT and risk studies for three quick clay risk zones that the line crosses have been carried out.

Result

The results are reported in the form of proposals for safety measures that include securing 2 quick clay zones, securing a total of 18 localities with regard to rockfall and earthslides from side terrain and implementation of measures for a total of 78 culverts that have been designated priority status 1, 2 and 3 (it is recommended that the measures are implemented within 3 years). A cost estimate has also been provided for implementation of the safety measures.