8.6 Facing installation and connection with nail heads

8.6.1 Hard facing

8.6.1.1 Single layer sprayed concrete without steel mesh may be applied if only to protect against erosion.

8.6.1.2 When using steel mesh and sprayed concrete, the steel mesh shall not create voids during spraying. Consideration shall be given to connections between each stage, tests for the sprayed concrete, protection of weep holes during spraying. When problems of stability of the mass or local stability appear, possible solutions are:

a) construction by alternate slots;
b) installation of the nails before earthworks operations;
c) spraying a thin protective concrete layer immediately after earthworks (avoids surface instability and effects of weathering on the ground).

8.6.1.3 Application of cast-in-place concrete may be used in accordance with the design requirements or the requirements of the system. The concrete shall comply with EN 13670.

8.6.1.4 Pre-cast facing elements may be used in addition to sprayed concrete at points of significant load transfer (e.g. nail heads).

8.6.1.5 The facing and the nail connection to the slope surface should fulfil the same requirement concerning durability as the rest of the soil nailing system.

8.6.2 Flexible facing

8.6.2.1 Facing, such as steel mesh, a suitable geosynthetic or steel netting, shall be installed according to the manufacturer's recommendation and according to the design requirement.

8.6.2.2 The connection to the slope surface shall be undertaken according to the requirements of the system. Connection shall be made of the flexible facing to the nails with suitable system in accordance with design requirement.

8.6.2.3 The facing and the soil nail connection to the slope surface should fulfil the same requirement concerning durability as the soil nail of the soil nailing system.

8.6.3 Soft facing

8.6.3.1 A soft facing of light metal mesh or grid with a geosynthetic sheet shall be placed and fixed in accordance to the system requirements.

NOTE Where specified, an underlying fine mesh or geo-grid may be installed for erosion protection. This may be a biodegradable geosynthetic for a temporary erosion control, which is to be replaced by vegetation cover.

8.6.3.2 The specified soft facing system shall be placed according to the system requirements.

8.6.3.3 Vegetation of slope: climatic and local conditions, such as site location, gradient, altitude, amount and frequency of precipitation, may influence the choice of a suitable seed mix and the greening method (e.g. hydro seeding, seeded geotextile).

8.6.3.4 The necessity for special vegetative cover and artificial irrigation shall be taken into account during both construction and service life.

8.6.3.5 Connection to the slope surface shall comply with the design specifications.

8.6.3.6 To ensure good connection between the facing, the soil nails and the slope appropriate soil nail head plates, claw plates or system fixtures should be used.

8.6.3.7 Around a facing boundary that is not reinforced by soil nails, pre-tensioning of connectors to appropriate fixed anchors can be required.

8.6.3.8 The facing and the nail connection to the slope surface should fulfil the same requirement concerning durability as the rest of the soil nailing system.

8.6.4 No modification to existing surface

8.6.4.1 The soil nail works can be constructed without any modification to the existing surface.

8.6.4.2 The existing low vegetation and structures shall be preserved.

8.6.4.3 If trees need to be removed, the root ball should be preserved.