Cross slopes

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In order to produce a path of adequate width across a slope it will be necessary to form a level ‘bench’. This can be done either by cutting a ‘bench’ into the slope or by building up to the level with a suitable bulk fill material. Carefully store top soil and any turfs that have been removed and use them to help protect bare slopes – turfs may need watering if stored for any length of time (remember to include provision for watering of turfs in any conditions of contract and specification).

The angle of the cut slope is important for stability of the path and is dependent on the strength of the soil and underlying material (e.g. glacial till or rock). In order to keep water off the path, you need to cut a sufficient width to include drainage between the bottom of back slope and edge of the path. If space is restricted and steeper slopes are required, you may need to use slope stabilisation methods, such as a geotextile or a retaining wall.

If you are building up a bench with bulk fill material, remove and store the vegetation and topsoil first and be sure that the imported bulk fill material has the strength to remain on the slope. Ensure that the fill part of the bench is formed in well compacted layers.

In some circumstances the material cut from the slope can be used as fill on the lower side of the slope. This will reduce, or eliminate, the amount of bulk fill material to be imported onto site.

Cut and fill method to bench a path

You can use ‘cut and fill’ technique on slopes where the cross gradient is less than 33% (1:3). Only use cut and fill if the soil is strong (i.e. does not contain a lot of clay) otherwise it will not remain stable when the path is used. Test the soil for strength using the ‘field heel test’ and look for granular, ‘gritty’ feeling soil. If the soil is weak, form the bench by only cutting material - this will produce a large amount of material for disposal on or off site.

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