Murphy Group/SCA Group
Services Supplied on this Project:
- Rock Stability Assessment
- Health and safety plans
- Stakeholder communications
- Rope Access
- Trackside working
Geo-Environmental Services Limited was instructed by SCA Group on behalf of J. Murphy & Sons Limited to undertake a Geotechnical Assessment on a cutting (approximately 110m in length) on the northern side of the track situated approximately 560m to the south-east of Berkswell Station near Coventry. It was understood that on 7th January 2017 near Berkswell Station, Coventry, a rock fall occurred within a railway cutting and sandstone blocks came to rest on the up main cess rail. As such, the objectives were to undertake a geotechnical preliminary risk assessment of the existing cutting.
- The site works were undertaken by means of rope access inspection over a period of five day shifts.
- To facilitate the inspection, vegetation was cleared from the slope by a rope access de-vegetation team from SCA Group.
- De-vegetation was kept to a minimum so as to minimise the risk of root mass degradation which might reduce the binding effect of the root-mass and promote slope instability.
- A visual inspection of any rock exposures was made which included recording joint or discontinuity spacing, bedding, rock exposure shape and structure.
- A series of vertical traverses were made along the length of the embankment to measure slope length and angle, so as to record slope cross section.
The inspection had identified that roots from trees and ivy had penetrated discontinuities causing root jacking of joints. An area of displaced blocks were observed angling down-slope. In addition, rock falls were noted along the entire length of the embankment. There was evidence of spalling by freeze-thaw action due to saturated soil packing in discontinuities. It was considered that applicable remedial techniques are likely to comprise dentition of rock overhangs, de-vegetation and draped rock netting over rock exposures to safely contain any rock falls. An urgent recommendation was made for preliminary action (scaling) on the rock face, in two areas to be undertaken. To determine drilling conditions within the existing soil slope and underlying sandstone bedrock for anchoring draped rock netting, it would be necessary to undertake intrusive followed by detailed slope stability analysis, modelling and design.