Examination of Earthworks Manual
|Publication Date:||2 September 2017|
This business process describes the procedures for carrying out earthwork examinations, and for identifying urgent actions to be taken.
The types of examinations include:
a) asset identification inspections;
b) reconnaissance inspections;
c) cyclical examinations;
d) rapid response examinations;
e) special examinations;
f) urgent defect reports;
g) devegetation inspections;
h) Examination checks.
This business process applies to all earthworks within the boundary of the Network Rail infrastructure (including approach embankments, approach cuttings, tunnel cuttings, slopes above tunnel portals, nailed or reinforced soil structures and any embankment that also acts as a coastal, estuarine or river defence - irrespective of its height).
NOTE 1: Approach embankments applies to overline bridges that are equal to or greater than 3 metres high, except those owned by a highway authority, roads authority or other competent authority.
NOTE 2: Reinforced soil structures apply to those whose face angle is less than or equal to 70 degrees to the horizontal.
It also covers outside party slopes which may impact the infrastructure, and can be examined using the Soil Cutting Hazard Index (SCHI), Soil Embankment Hazard Index (SEHI) and the Rock Slope Hazard Index (RSHI).
For outside party slopes where there is evidence or concern that the failure of the slope presents an unacceptable risk to the safe operation or performance of the railway the procedures described in NR/L2/CIV/086 will be adopted.
Where the outside party is unable to provide a satisfactory management policy for the slope, or demonstrate by other means that it is being managed in a satisfactory manner, the slope will, so far as is lawful, be subject to a cyclical examination. If the slope cannot be examined, then a Geohazard Assessment process shall be followed in line with NR/L2/CIV/086/Mod04.
This business process does not apply to:
a) examinations specifically carried out to assess ground movements resulting from mineral extraction, landfill operations or a subterranean fire (refer to NR/L3/CIV/037);
b) the examination of vegetation (other than the factors affecting slope stability) (refer to NR/L2/TRK/5201);
c) examinations specifically carried out to assess drainage condition and structural integrity (refer to NR/L3/CIV/005);
d) the examination of nailed or reinforced soil structures steeper than 70 degrees, retaining walls and gabion walls - other than the factors that may indicate instability of the slope (refer to NR/L3/CIV/006);
e) the examination of coastal, estuarine or river defence works that are not also embankments (refer to NR/L3/CIV/006);
f) the examination of outside party slopes which may impact the infrastructure which cannot be examined using the SCHI, SEHI and RSHI (refer to NR/L2/CIV/086/Mod04)
This business process does not cover:
1. Health and safety requirements applicable to operational safety and emergency evacuation procedures.
2. The commercial and all the organisational responsibilities for delivering the requirements of the Standard.
Earthwork examinations are carried out to check the likelihood of failure of the asset.
These examinations are required to confirm the asset failure likelihood and to qualitatively assess its ability to perform its function.
This business process manages the control, 'earthwork examination', mitigating the following risks:
a) loss of track support or track geometry;
b) slope failure leading to loss of kinematic envelope or track geometry.