Safety in Excavation

EXCAVATION Reference Standard IS 3764 : 1992

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

Excavation Hazards 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 Vehicular traffic Adjacent structures

…..Excavation hazards Mobile equipment. Access / Egress

Soil collapse

So, What is required ?

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

Soil Classification 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

Preventing Soil Collapse Soil 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 Stable Rock : 900 Type A - 3/4:1 530 Short term up to 12’ -630 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

Simple Sloping -Type A Soil Supported or Shielded Vertically-Sided Lower Portion

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)

Basic components of shoring

Shoring in Footing foundation OUTWARD SLOPE ( 35* TO 40*) CONSIDERING ONGOING RAINY SEASON

Arrangements in Water Logged Area SUPPORT TO THE WALL OF EXCAVATED PIT

Timber Shoring Installations REFER TO DESIGN ENGR.

Utilities Underground PERMIT SYSTEM

EFFECTS OF UTILITIES ABOVE GROUND UNDER GROUND

EFFECTS OF UTILITIES EXPLOSION FIRE

UTILITIES Obtain work permit and get clearances from the concerned PREVENTION Obtain 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 water Surface 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 stability Shoring Bracing Evaluation 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 – Ramps with slope not more than 15o @ 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 Safety Vests Fencing Illumination

Traffic Control Device & Vest

Fencing Physical barricades required always Hard 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 diversions Pedestrian walkway diversions

Caution Signs Reflective Cone Barricades

ILLUMINATION Temporary Lightings: Sufficient Area Lighting. Emergency Lighting with Power back up.

Excavation Inspections Daily 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

Beyond All

Safety awareness – Supervision Develope - 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 ?

Thank You & Have a Safe day