• Excavation Hazards : Types, Effects and Preventive Measures

    by  • December 18, 2013 • Articles, Construction Information, Editorial • 0 Comments

    excavation_hazard_preventive_measure_civilengineerEXCAVATION HAZARDS-

    THEIR EFFECTS AND PREVENTION

    Different types of hazards are associated with excavation of soil. These hazards should be identified and preventive measures should be taken to avoid any accident at construction sites. The following table highlights hazards associated with excavation of soil during construction, their types, effects and preventive measures.

    TYPE OF EXCAVATION

    TYPE OF HAZARD

    EFFECT OF HAZARD

    PREVENTIVE MEASURES

    Pit excavation upto 3m

    Falling into pit

    Personal injury

    Provide guard rails / barricade with warning signal

    Provide atleast two entries / exits

    Provide escape ladders

    Earth collapse

    Suffocation /breathlessness

    Buried

    Provide suitable size of shoring and strutting if required.

    Keep soil heaps away from the edge equivalent to 1.5m or depth of pit whichever is more.

    Don’t allow vehicles to operate too close to excavated areas. Maintain atleast 2m distance from the edge of cut.

    Maintain sufficient angle of repose. Provide slope not less than 1:1 and suitable depth of excavation in all soils except hard rock.

    Battering / benching the sides.

    Contact with buried electric cable

    Gas / Oil Pipelines

    Electrocution

    Explosion

    Obtain permission from competent authorities prior to excavation if required.

    Locate the position of buried utilities by referring to plant drawings.

    Start digging manually to locate the exact position of buried utilities and thereafter use mechanical means.

    Pit excavation beyond 3m

    Same as above plus flooding due to excessive rain / underground water

    Can cause drowning situation

    Prevent ingress of water

    Provide ring buoys

    Identify and provide suitable size dewatering pump or well point system

    Digging in the vicinity of existing building / structure

    Building / structure may collapse

    Loss of health and wealth

    Obtain prior approval of excavation method from local authorities.

    Use under-pinning method.

    Construct retaining wall side by side.

    Movement of vehicles / equipments close to the edge of cut.

    May cause cave-in or slides.

    Person may get buried.

    Barricade the excavated area with proper lighting arrangements.

    Maintain atleast 2m distance from edge of cut and use stop blocks to prevent over-run.

    Strengthen shoring and strutting.

    Narrow deep excavations for pipelines etc.

    Same as above plus frequent cave-in or slides

    May cause severe injuries or prove fatal.

    Battering / benching of sides.

    Provide escape ladders.

    Flooding due to hydro-static testing

    May arise drowning situation

    Same as above.

    Bail out accumulated water.

    Maintain adequate ventilation.

    Rock excavation by blasting

    Improper handling of explosives

    May prove fatal

    Ensure proper storage, handling and carrying of explosives by trained personnel.

    Comply with the applicable explosive acts and rules.

    Uncontrolled explosion

    May cause severe injuries or prove fatal.

    Allow only authorized persons to perform blasting operations.

    Smoking and open flames are to be strictly prohibited.

    Scattering of stone pieces to atmosphere

    Can hurt people

    Use PPEs like goggles, face mask, helmets etc.

    Entrapping of persons / animals

    May cause severe injuries or prove fatal

    Barricade the area with red flags and blow siren before blasting.

    Misfire

    May explode suddenly

    Do not return to site for atleast 20min or unless announced safe by designated person.

    Piling work

    Failure of pile-driving equipment

    Can hurt people

    Inspect piling rigs and pulley blocks before the beginning of each shift/

    Noise pollution

    Can cause deafness and psychological imbalance.

    Use personal protective equipments like ear plugs, muffs etc.

    Extruding rods/casing

    Can hurt people

    Barricade the area and install sign boards

    Provide first aid

    Working in the vicinity of live-electricity

    Can cause electrocution / asphyxiation

    Keep sufficient distance from live electricity as per relevant standard codes.

    Shut off the supply if possible.

    Provide artificial / rescue breathing to the injured.