C9.2 Excavation Flashcards
Methods to avoid excavation
micro tunnelling
directional drilling
impact moling
pipe bursting
CDM reg 22
Steps to be taken to prevent danger to any person
protection from collapse
protection from material falling in
protection from people / equipment falling in
prevent surrounding ground being overloaded
excavation hazards
collapse of sides equipment / material falling in people falling in flooding gases / explosion - methane build up fumes - contaminated ground collapse of nearby structures / under mined foundations
measures to support excavation sides
trench box
shoring
steel sheets / piles
measures to prevent collapse of nearby structures
shoring / supports
measures to prevent falling in
guard rails
lit at night
stop blocks / sleepers
covers over shallow trenches
excavation inspection reports
by competent person
completed within 24 hrs
report kept on site
conduct weekly if no adverse event
contents of excavation inspection report
name / address of person inspection was done for location of work description of work date / time of inspection details of any H&S issues details of any action taken details of further required action name / position of person writing report
underground services
gas electric sewerage other pipes - oil, chemical, petrol fibre optics
excavation SSW
planning avoidance of services protection / support of services material handling waste public protection
how to detect services
plans - may be out of date
detection devices
CAT scanner (cable avoidance tool)
ground penetrating radar
measures to protect underground services
detect re-route support hand dig within 0.5 metres with insulated hand tools fencing hung up labelled
mechanisms for excavation collapse
loose soil water logged heavy plant too close vehicles cause vibration inadequate support excavation below level of shoring
mechanisms for falls of people / items into excavations
materials too close to edge excavation too close to building excavation edge not clear no barriers no lighting poor position / lack of ladders unsuitable / no vehicle ramps no stop blocks vehicles too close
measures to control water ingress
pumps
advice from EA
if within 10 metres, Consent for Works Affecting Watercourses from EA
CDM Reg 31
start of shift inspections by competent person
inspections after any event that might affect stability of excavation
inspections after any material fall
no work if adverse inspection findings until fixed
considerations ref shoring
subsoil - if wet, use metal sheets
duration of works - trench / drag box for short duration
type of work - trench / drag box for pipe work
minimise length of excavation trench
flooding risk
excavation depth
number of people in excavation hole at any time
360 degree excavator hazards
impact with pedestrian / vehicle from swinging boom impact from bucket contents falling from bucket hydraulics under pressure overturn contact with overhead power lines
360 degree excavator control measures
trained users not overloading maintenance / inspection pedestrian segregation signage driver visibility aids - cameras / mirrors high viz roll over & cab impact protection seatbelts
contents of a permit to dig form
principal contractor name sub contractor name permit number date location size /depth service plans yes/no cable locating equipment yes/no services marked out yes/no trial holes needed yes/no precautions for overhead power yes/no sketch / copy of plans date / time of excavation signed by issuer and receiver
