Safety in Excavation

IS 3764 : 1992

EXCAVATION

ExcavationExcavation.

Any man made cut, cavity or depression in the earth’s surface formed by earth.

•Soil Collapse

•Utilities

•Hazardous atmospheres

•Adjacent structures

•Falls / Falling loads

•Access / Egress

•Vehicle traffic

•Mobile equipment

•Water accumulation

•Cave-in

Excavation Hazards

Cave-in / Soil collapse

Improper shoring.

…..Excavation hazards

Collapse of shoring

Falling loads

Excavation hazards

Slip & fall of workmen

Utilities

…..Excavation hazards

Adjacent structures

…..Excavation hazards

Vehicular traffic

Access / Egress

Mobile equipment.

…..Excavation hazards

Soil collapse

Prior to Excavation•Obtain a work permit

•Check Ground / Soil condition

• Check Ground / Surface Water

• Check the Location of Water Table

• Check Under ground / Overhead

utilities

• Adjacent buildings

• Dynamic load / Traffic

•Type A :

Clay, sandy clay, clay loam

• Type B :

Angular gravel (similar to crushed rock), silt, silt loam, sandy loam

• Type C:

Gravel, sand, loamy sand,Submerged soil or soil from which water is freely seeping; or Submerged rock that is not stable

Soil Classification

Preventing Soil CollapseSoil classification (Type a, b, or C)

• Sloping • Benching• Placing a shield.• Shoring(Timber / Aluminum shoring• Sheet piling

Your choice of protection

•Sloping

•Benching

•Shoring

•Shields

Designed by a Registered Project Engineer

Simple Sloping

Short term up to 12’ -630

•Stable Rock : 900

•Type A - 3/4:1530

Note :Greater than 20 feet deep shall be designed by a registered

professional engineer.

Simple Sloping -Type A Soil

Unsupported Vertically-Sided Lower Portion <12 ft

Unsupported Vertically-Sided Lower Portion <8 ft

Supported or Shielded Vertically-Sided Lower Portion

Simple Sloping -Type A Soil

Simple Sloping

Type B - 1:1 450

Type C - 1½ :1 340

Note :Greater than 20 feet deep shall be designed by a registered

professional engineer.

Benching

Type A

Type B (cohesive)

OUTWARD SLOPE ( 35* TO 40*) CONSIDERING ONGOING RAINY SEASON

SUPPORT TO THE WALL OF

EXCAVATED PIT

Timber Shoring Installations

REFER TO DESIGN ENGR.

UtilitiesUnderground

PERMIT SYSTEM

ABOVE GROUND UNDER GROUND

EXPLOSION FIRE

UTILITIES

PREVENTIONObtain work permit and get clearances

from the concerned Electricity Water & Sewage Pipeline Communication Oil & Gas Pipe Line

Use Detectors ( for More Reliable)

Water Accumulation

Ground waterSurface water

Hazardous Atmospheres Never Start Work if,• Oxygen Level less than 19.5 %• Permissible limit of the toxic gases

exceeded.• More than 20 % of Lower Explosive Limit.

PRECAUTIONS• Ventilation to over come the above said.• Blocking the source, incase of toxic and

flammable gases. (Using other effective controls to reduce the level

of atmospheric contaminants to acceptable levels)

Adjacent Structures

Ensure structure stabilityShoringBracingEvaluation by

Professional

FALLING LOAD Gravity Weight of soil pile Weight of near by structures Weight of personnel &equipment Vibration

PREVENTION Never operate a construction equipment within 2.5 m from the

edge of the excavation. Stacking the material 1 Meter away from the edge of the

excavation.

Access

–Ladders –

•@ every 9.14 m Length –

Normal Operations

•@ every 4.6 m length –

Hazardous operation

–Ramps with slope not more than

15o

–Stairs cut on earth

Vehicle Traffic

Control Measures

• Traffic Management Plan• Traffic Control• Traffic Safety Vests• Fencing • Illumination

FencingHard Barrication shall be

provided, in the fall prone areas and if depth is more

Physical barricades required always

Must be placed 2m away from excavation edge.

Standard fall protection required for vertical falls over 1.3m

Traffic diversionsPedestrian walkway diversions

Reflective Cone Barricades

Caution Signs

Temporary Lightings:

Sufficient Area Lighting.

Emergency Lighting with Power back up.

ILLUMINATION

Excavation InspectionsDaily Inspections by Competent Person

Start of shift, as needed, following rainstorms or other hazard-increasing event Possible cave-ins Protective system failure Water accumulation Hazardous atmospheres

Safety awareness – SupervisionDevelope - personnel interested on Safety, Safe work procedures considering the ground

realities.Awareness and motivating the supervisors

concerned,Develop system to report, analyze and

prevent Near-miss cases.Developing gang leaders and attitude,

Any Questions ?