Safety in Excavations Presentation

Safety in ExcavationsSafety in Excavations

A guided study of understanding

the risks and dangers in excavation work

Topics to be DiscussedTopics to be Discussed

Soil Types Shear Strength Collapse Types Strength Factors Protective Measures


In General:In General: An employer is required to provide

safe means of access to and egress from a work area above or below ground level by means of stair, ladder, runway or ramp.

The access way must be well maintained well-lit, clear of obstructions, and be suitable abrasive to ensure firm footing for workers.


Excavation work cannot commence until the Labour Division has been notified and the employer has received a registration number and has notified public utilities.

If the employer does not perform the excavation in accordance with the Construction Industry Safety Regulation of the Workplace Safety and Health Act, the registration may be revoked and the excavation shut down.


Soil TypesSoil Types

Soil TypesSoil Types

Stable Rock Type A Soil Type B Soil Type C Soil Layered Geological Strata


Shear StrengthShear Strength


“ “ The capacity of a material The capacity of a material to resist the internal and to resist the internal and external forces which slide external forces which slide past each other “past each other “


Cohesion The stickiness of the soil; a greater

amount of clay than sand.

Internal Friction A result of particle shape.


Strength Strength FactorsFactors

Strength FactorsStrength Factors

Water Vibrations Erosion and Weathering Excavation Depth Slope Steepness Degree of Soil Compaction


Collapse TypesCollapse Types


Zone of Exposure


Zone of Exposure Spoil Pile Slide


Zone of Exposure Spoil Pile Slide Side Wall Shear


Zone of Exposure Spoil Pile Slide Side Wall Shear Slough – in


Zone of Exposure Spoil Pile Slide Side Wall Shear Slough – in Rotation


Shoring TechniquesShoring Techniques


Engineers are often required to design shoring, which is a construction procedure used specifically to maintain the stability of the walls of an excavation and provide protection to workers who may enter the excavation


Accidental Falling Entry

Excavation sites cannot be crowed with anything such as piles of excavated material or excavation equipment which might accidentally fall into the excavation.

All work areas adjacent to public walkways must be adequately guarded or barricaded by fences, guardrails or a covering sufficient to prevent persons from falling into the excavation.


Shafts and Tunnels

Due to the specific nature and hazards of the work, a professional engineer may be required to design a support structure for a shaft or tunnel prior to commencement.

At least one worker in each work crew must be experienced in the type of work being performed in shaft and tunnel excavations, and at least one worker is required to be trained in first aid.


Access Way

Employers must surround the opening to an underground excavation with a firm, level area and a protective barrier (at least 1 meter in height) surrounding it.

The access way must be secured with a cover to prevent unauthorised entry.

Access landings, the bottom of shafts and tunnels, and other similar work areas must be kept free of loose mud and other accumulations of debris.


Atmosphere

Every employer must provide a suitable ventilation system in a shaft or tunnel excavation to ensure that there is no lack of oxygen and that concentrations of toxins in the atmosphere are minimised.

No employer shall allow internal combustion engines to be used in underground work areas unless the engines are properly engineered to do so.


Illumination

Every employer must provide electrical illumination for the full length of the tunnel and at the face of the excavation where inadequate natural light is present.

Where electrical illumination is used in an underground excavation, employers are required to provide an emergency lighting system.


First Aid in Shafts and Tunnels

Employers must ensure that: At least one worker holding a valid first aid

certificate must be present during each shift. A first aid kit is provided in the immediate

vicinity of the entrance to a shaft or tunnel. A basket stretcher and blankets are provided

at each worksite. Workers are instructed in proper underground

rescue procedures.


Flammable and Combustible Hazards

Flammable and combustible liquids shall not be used underground unless they are stored in accordance with the Manitoba Fire Code.

Effective means for extinguishing a fire in an underground excavation must be provided where combustible or flammable materials may be present.


Wood Support


Wood Support Screw Jacks


Wood Support Screw Jacks Hydraulic Shores


Wood Support Screw Jacks Hydraulic Shores Spacing


Wood Support Screw Jacks Hydraulic Shores Spacing Trench Cages

Concluding RemarksConcluding Remarks

Excavation Work is a highly dangerous Excavation Work is a highly dangerous industry. Safety standards need to be industry. Safety standards need to be implemented and stringently implemented and stringently maintainedmaintained

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Safety in Excavations Presentation