1. The Rhuallt Hill Rock Cutting North Wales Alun Roberts Pejman Keikha

2. Introduction A 1km long downhill section of the A55 North Wales coastal road. A 1km long downhill section of the A55 North Wales coastal road. Allowing traffic to enter and leave the Vale of Clwyd. Allowing traffic to enter and leave the Vale of Clwyd. Consists of 2 deep rock cuttings as well as a large embankment across the valley floor. Consists of 2 deep rock cuttings as well as a large embankment across the valley floor.

3. Introduction The height of the cuttings vary up to 27m. The height of the cuttings vary up to 27m. The roadway curves through the hillside avoiding a potentially intrusive notch in the landscape. The roadway curves through the hillside avoiding a potentially intrusive notch in the landscape. The slope of the cuttings vary from a graded out 1:2 at the top to a near vertical 1:5 slope at road level. The slope of the cuttings vary from a graded out 1:2 at the top to a near vertical 1:5 slope at road level.

4. Geological Aspects The cutting was cut through a monotonous sequence of mudstones and siltstones of the Nant-Y-Glyn flags of Silorian age The cutting was cut through a monotonous sequence of mudstones and siltstones of the Nant-Y-Glyn flags of Silorian age The strata generally dip at about 25° along the line of the cutting. The strata generally dip at about 25° along the line of the cutting. Several transverse faults intersect the cutting and local discontinuities have adverse dips and orientations. Several transverse faults intersect the cutting and local discontinuities have adverse dips and orientations.

5. Rock Face Stabilisation Methods Rock Anchors Rock Anchors –650 No –Lengths up to 23m –Monobar Rock Anchors –Multistrand Rock Anchors

6. Rock Face Stabilisation Methods Rock Bolts Rock Bolts –Mechanically Anchored Rock Bolts –Resin Anchored Rock Bolts

7. Rock Fall Protection Measures Rock Catch Ditch Rock Catch Ditch Barrier Fence Barrier Fence

8. Thank you for listening Any Questions?