Negotiated - Compiled Reference Document - RAL25 0011 (As Published)

 

APPENDIX G - SOME GUIDELINES FOR HILLSIDE CONSTRUCTION

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Pipes.
‘Where structural distress is evident see advice.
If seepage observed determine cases or seek advice on consequences.

 

GOOD ENGINEERING PRACTICE POOR ENGINEERING PRACTICE
ADVICE
GEOTECHNICAL Obtain advice from a qualified, experienced geotechmical practitioner at early | Prepare detailed plan and start site works before
ASSESSMENT stage of planning and before site works. geotechnical advice.
PLANNING = _
SITE PLANNING Having obtained geotechnical advice. plan the development with the risk | Plan development without regard for the Risk.
arising from the identified hazards and consequences in muind.
DESIGN AND CONSTRUCTION ¥
‘Use flemtble structures which incorporate properly desiened brickwork, timber | Floor plans which require extensive cutting and
HOUSE DESIGN | 0! tee! Stames, timber or pane! clactime, filling.
Consider use of split levels. Movement intolerant structures.
Use decks for recreational areas where appropriate.
SITE CLEARING Retain natural vegetanon wherever practicable. Indiscrmmnately clear the site.
ACCESS & Satisfy requirements delow for cuts, fills, retaining walls and drainage. Excavate and fill for site access before
DRIVEWAYS Council spectfications for grades may need to be modified. geotechnical advice
Driveways and parking areas may need to be fully supported on piers.
EARTHWORKS Retain natwal contours wherever possible. Tndiscrmmatory bulk earthworks.
Minimise depeh Large scale cuts and benching.
Ours Support with engineered retaining walls or batter to appropriate slope. Unsupported cuts
Provide drainage measures and erosion control Ignore drainage requirements
‘Minute height ‘Loose or poorly compacted fill, which if it falls,
Strip vegetation and topsoil and key into natural slopes prior to filling. way flow a considerable distance including
Use clean fill materials and compact to engineering standards. onto property below.
Fars Batter to appropriate slope or suppart with engineered retaining wall Block natural drainage lines.
Provide surtace dramage and appropriate subsurface drainage. Fill over existing vegetation and topsail.
Include stumps, trees, vegetation, topsoil
boulders, building mibble etc in fill
Rock Ourcrors | Remove or stabilise boulders which may have unacceptable risk. Distrd or undercut detachad Blocks or
& Bowers Support rock faces where necessary. boulders.
Engineer design to resist applied soi! and water forces. Construct a structurally inadequate wall such as
RETADING Found on rock where practicable sandstone flagging, brick or umreinforced
WALLS Provide subsurface drainage within wall backfill and surface drainage on slope | blockwork
above Lack of subsurface drains and weepholes.
Construct wall as soon as possible after cut fill operation.
Found within rock where pracacable Found on topsoil, loose 11 detached boulders
FOOTINGS Use rows of piers or strip footings oriented up and down slope. orundercut cliffs.
Desizm for lateral creep pressures if necessary.
Backfill footing excavations to exclude ingress of surface water.
Engineer designed
Support on piers to rock where practicable.
SWIMMING POOLS | Provide with under-drainage and gravity drain outlet where
Design for high soil pressures which may develop on uphill side whilst there
muay be lirtle or no lateral support on downhill side
DRAINAGE
Provide at tops of cut and fill slopes. Discharge at top of fills and cuts.
Discharge to street drainage or natural water courses Allow water to pond on bench areas.
SURFACE Provide general fails to prevent blockage by siltation and incorporate silt traps
Line to minimise mnfilzation and make flexible where possible
Special structures to dissipate energy at chanzes of slope and/or direction.
Provide filter around subsurface drain Discharge roof nmoé into absorption trenches.
Sunsunrace | Provide drain behind retaining walls.
Use flexible pipelines with access for maintenance.
Prevent inflow of surface water.
Semck Usually requires pump-put or main: sewer systems; absorption trenches may | Discharge sullage directly onto and into slopes.
Surtage be possible im some areas if risk is acceptable. Use absorption menches without consideration
Storage tanks should be water-tight and adequately founded. of landslide nck.
EROSION Control erosion as this may lead to instability. Failure to observe earthworks and dramage
CONTROL & Revegetate cleared area. recommendations when landscaping.
LANDSCAPING
DRAWINGS AND SITE VISITS DURING CONSTRUCTION
DRAWINGS Building Applicanon drawings should be viewed by geotechnical consulmnt
STE VISITS Site Visits by consultant may be appropriate durmz construction’
INSPECTION AND MAINTENANCE BY OWNER
OWNER’S Clean dramage systems; repair broken joints in drams and aks im supply
RESPONSIBILITY