Highway Slope Manual

28
Table 2.2 Geotechnical Haards That Need to be Considered for a Highway Project
Existing man-made slope All substandard features the failure of which could affect the route or could be
features that could affect or caused by the works. All features which are up to standard but could be
be affected by the project affected by the works (e.g. due to installation of buried water-carrying services,
changes in surface and subsurface water flow regime and lateral loads that will
be imposed by new highway structures).
an-made slope features
that will be formed along
the route
Natural terrain landslide
hazards
Other geotechnical hazards
Hazards associated with the
geotechnical works
All cut slopes, fill slopes and retaining walls, with particular attention drawn to
those to be formed in difficult ground, e.g. steep hillside, adverse geological
conditions such as presence of dykes, faults and other weak zones, and adverse
surface water or groundwater conditions.
All natural terrain landslide hazards, including debris avalanches, debris slides,
channelised/non-channelised debris flows, boulder/rock falls, gully and other
forms of erosion and deep-seated ground movements (see Figure 2.3), which
could affect the route or could be caused by the works. Guidance on natural
terrain hazard review and natural terrain hazard assessment is given by Ng et al
(2000).
All other hazards, in cluding the presence of soft ground and karstic areas.
All hazards associated with construction of the geotechnical works, e.g. rock
blasting near sensitive receivers, open or supported excavations including those
for cut and cover tunnel construction and temporary diversion of surface water,
traffic diversion and/or road closure to mitigate the hazards during construction.
Figure 2. Natural Terrain Landslide Haards Posed to a Highway