Local Road Management Manual 439 Excavation/cutting Cutting is required where the natural ground level lies above the proposed alignment of the road. For road rehabilitation it is not expected that signiifcant amounts of cutting will be needed. If it is necessary to increase cuttings for road widening or improving sight lines or other reasons this would be considered as major road improvement. Cuttings in sound rock can often be vertical, but in weathered rocks and soils it is necessary to use shallower slopes. The stability of cuttings depends not only on the material but also on the height of the cutting and on the water table conditions. In the absence of any other information, Table 2 gives preliminary advice on suitable cutting slopes, although the slope may need to be adjusted for local conditions. For higher slopes and for problem soils such as loose or soft soils and material with a high organic content, specialist professional advice should be sought. Table 2. Preliminary advice for cutting slopes Soil Type Water Table Cut Height 0-3 m Cut Height 3-6 m Gravels, sands Low 1 V:1.5 H 1 V:1.5 H Moderate 1 V:1.5 H 1 V:1.5 H High 1 V:1.5 H 1 V:1.5 H Clayey gravels, Low 1 V:1 H 1 V:1 H sands Moderate 1 V:1 H 1 V:1 H High 1 V:1 H 1 V:1.5 H Stiff Clays Low 1 V:1.1 H 1 V:1.1 H Moderate 1 V:1.1 H 1 V:1.1 H High 1 V:1.1 H 1 V:1.1 H Soft clays Obtain specialist Obtain specialist advice advice Organic soils Obtain specialist Obtain specialist advice advice