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Excavation Hazards : Types, Effects and Preventive Measures

EXCAVATION 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.

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