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Which of the following is the greatest risk of an excavation?

The greatest risk in an excavation is a cave-in. Employees can be protected through sloping, shielding, and shoring the excavation. A competent person is responsible to inspect the excavation. Other excavation hazards include water accumulation, oxygen deficiency, toxic fumes, falls, and mobile equipment.

What are the risk of excavation?

There are a range of health and safety risks associated with excavation work including:

  • falls from one level to another.
  • the fall or dislodgement of earth or rock.
  • vibration and hazardous noise.
  • exposure to an airborne contaminant .

What is most likely to cause an excavation to collapse?

Excavated spoil, plant or materials should not be stored close to the sides of excavations as loose material can fall in. The extra loading can make the sides of the excavation more likely to collapse. Prevent people from falling into excavations by substantial barriers around the edges.

What is the main hazard when working in an excavation?

Every year people are killed or seriously injured by collapses and falling materials while working in excavations. They are at risk from: Excavations collapsing and burying or injuring people working in them; material falling from the sides into any excavation; and.

What you should do before you begin an excavation?

What you should do before you begin an excavation?

  • Identify the soil type(s) related to the excavation or trench you are going to dig.
  • Look for the legislative requirements that apply in your jurisdiction and the type of protective measures to be taken.
  • Locate all buried services.

At what depth is an excavation considered a confined space?

four feet

What are 3 main protection methods against cave-ins?

To prevent cave-ins: SLOPE or bench trench walls. SHORE trench walls with supports, or. SHIELD trench walls with trench boxes.

What is the minimum oxygen level for a confined space?

19.5 %

What are the steps of excavation?

The excavation process includes:

  1. setting corner benchmarks.
  2. surveying ground and top levels.
  3. excavation to the approved depth.
  4. dressing the loose soil.
  5. marking up the cut off level.
  6. the construction of dewatering wells and interconnecting trenches.
  7. marking the boundaries of the building.
  8. the construction of protection drains.

How can we prevent excavation?

Provide protection by:

  1. Set spoils and equipment at least 2 feet back from the excavation.
  2. Use retaining devices, such as a trench box that will extend above the top of the trench to prevent equipment and spoils from falling back into the excavation.

How many types of excavation are there?

8 Types

What are the tools used for excavation?

Types of Soil Excavation Tools and Machines in Construction

  • Spade.
  • Shovel.
  • Hoe.
  • Trowel.
  • Rake.
  • Pick axe.
  • Mattock.

What are the types of equipments?

Different types of heavy equipment commonly used in the construction are as follows:

  • Excavators.
  • Backhoe.
  • Dragline Excavator.
  • Bulldozers.
  • Graders.
  • Wheel Tractor Scraper.
  • Trenchers.
  • Loaders.

What is a digging machine called?

Excavator. Also known as diggers, mechanical shovels and trackhoes (tracked excavators), these versatile machines are available with a wide variety of attachments.

What is trench excavation?

TRENCH: An excavation in which material removal forms a narrow opening in the ground. Unlike large excavations, a trench is generally deeper than it is wide. OSHA considers an excavation to be a trench if it is 15 feet wide or less at the bottom of the excavation.

How deep should a trench be?

Trenches 5 feet (1.5 meters) deep or greater require a protective system unless the excavation is made entirely in stable rock. If less than 5 feet deep, a competent person may determine that a protective system is not required.

What are the 4 types of trenches?

  • Front-line Trench. This type of trench was also known as the firing-and-attack trench.
  • Support Trench. This trench was several hundred yards behind the front-line trench.
  • Reserve Trench. The reserve trench was several hundred yards behind the support trench.
  • Communication Trench.

What does Trench mean?

a long, narrow excavation in the ground, the earth from which is thrown up in front to serve as a shelter from enemy fire or attack. trenches, a system of such excavations, with their embankments, etc. a deep furrow, ditch, or cut.

Why were the trenches so dangerous?

Life in the trenches was very difficult because they were dirty and flooded in bad weather. Sustained exposure to the wet, muddy conditions could cause Trench Foot, which sometimes would result in the foot being amputated. Cold weather was dangerous too, and soldiers often lost fingers or toes to frostbite.

What was living in a trench like?

Trenches were long, narrow ditches dug into the ground where soldiers lived. They were very muddy, uncomfortable and the toilets overflowed. These conditions caused some soldiers to develop medical problems such as trench foot. In the middle was no man’s land, which soldiers crossed to attack the other side.

Is a trench a hole?

A trench is a deep and narrow hole, or ditch, in the ground, like the kind soldiers on frontlines might dig to give themselves shelter from the enemy. A natural trench may also be a deep hole on the bottom of the ocean.

What is the safest way of entering and exiting a deep excavation?

Prevent people and materials falling in – with barriers strong enough not to collapse if someone falls against them. Keep plant and materials away from the edge. Avoid underground services – use relevant service drawings, service locating devices and safe digging practice. Provide ladder access to get in and out.

Why did they use trenches in ww1?

During WWI, trenches were used to try to protect soldiers from poison gas, giving them more time to put on gas masks. Dysentery, cholera, typhoid fever, and trench foot were all common diseases in the trenches, especially during WWI. Gigantic rats were common in the trenches of WWI and WWII.

How trench is formed?

Trenches are formed by subduction, a geophysical process in which two or more of Earth’s tectonic plates converge and the older, denser plate is pushed beneath the lighter plate and deep into the mantle, causing the seafloor and outermost crust (the lithosphere) to bend and form a steep, V-shaped depression.