Highway Slope Manual

-AA
(v)
relevant services and utilities records.
(b)
Carry out a detailed Aerial Photograph 1nterpretation (AP1) for the proposed
alignment(s) and nearby, which shall involve a study of all available aerial
photographic records to:
(i)
(ii)
(iii)
establish the history of development along the route alignment(s),
determine the nature, history and stability of man-made slopes, and
establish landslide history of natural terrain as required to support a
Natural Terrain Hazard Assessment if this is needed.
(c)
Carry out a detailed walkover survey of the proposed alignment(s) and nearby to:
(i)
(ii)
review and update the records presented in the GR Report on key natural
terrain and man-made geotechnical features, signs of ground instability
and geotechnical hazards, and
undertake the geological, geomorphological and seepage mapping, and
structural geological measurements.
(d)
(e)
(f)
(g)
(h)
Critically review and revise, if necessary, the objectives and scope of the ground
investigation (G1) works as recommended in the GR Report. Prepare a G1 plan
which shall contain the requirements of ground investigation works, including
any field testing and laboratory testing, and groundwater and ground movement
monitoring needed. Agree with the Employer the scope of the G1 and the method
of procurement.
Procure or arrange to carry out and supervise the G1 works together with the
necessary topographical surveys, field testing, laboratory testing and monitoring
works to determine the subsurface conditions (including confirmation of the
locations of services and utilities) and the nature and areal extent of the
geotechnical hazards.
Carry out a Natural Terrain Hazard Assessment (NTHA) for the highway project,
in accordance with the guidelines issued by the Geotechnical Engineering Office,
and assess the need for hazard mitigation measures.
Check records to determine whether there is documentary evidence to confirm if
the stability of any existing man-made slope features is up to current safety
standards. 1f such documentary evidence is inconclusive, assess the stability of
those features or where practicable, recommend prescriptive measures to upgrade
the features.
Assess the effect of existing and new man-made slope features (e.g. those in the
vicinity of natural terrain) on the stability of the natural terrain.