There are countless dangers that construction site workers are exposed to. From heavy equipment and elevated heights to unstable structures and unstable ground, these environments are filled with hazards that can lead to life-changing injuries. This is especially true when work areas aren’t properly managed and staged.
Surprisingly, being buried alive is one risk that many in construction routinely face. With approximately 35 people dying in excavation-related accidents each year, there are a number of things that companies can and must do to keep their teams safe.
Trenching and Excavation in Construction
During the formative stages of most construction projects, trenching and earth-moving are essential steps. Trenches are created by digging narrow ditches with both large and small earth-moving tools so that the resulting cavities are significantly deeper than they are wide.
Although trenches can be formed with hand tools and heavy digging equipment, these can also be unstable depressions that naturally exist within the earth’s surface, that are then further defined by organized soil removal.
The Importance of Land Surveys in Excavation
Land surveys are typically performed ahead of any excavation project with the intent of identifying all power, sewer, water or internet lines. These surveys can additionally identify other forms of underground service including various piping and communications-related infrastructure. Cave-ins frequently occur in locations that have not been properly surveyed ahead of excavation, or that have not been surveyed at all.
Without surveying, there is always the risk of encountering service lines and disrupting them. These disruptions can loosen large amounts of earth at once, thereby causing a cave-in. However, the most common cause of trench cave-ins is sliding soil. Trench work often involves the use of forceful equipment such as:
- Heavy diggers and earth movers
Excessive vibrations from heavy and percussive equipment combined with extraordinary pressure on surrounding soils can cause loose earth to come tumbling into trenches even while workers remain present.
Water, Soil Erosion and the Local Climate
Monitoring soil stability is always an important task whenever excavation is being performed. Water can contribute to soil erosion and cause soil slides, particularly in projects in which trenches are created or positioned below the water table. Soil surveys can identify unstable soil conditions that are more prone to water erosion such as clay-like soil or sandy soil.
Running into a water line or performing work during or immediately after rainfall can also lead to soil slides. Even freezing and thawing of certain soil types can greatly increase the likelihood of a trench wall collapse by adding more moisture to the earth. Sadly, given that many construction projects are driven by incredibly tight deadlines, each year thousands of people are victims of unsafe working conditions in recently trenched or excavated areas.
Mitigating the Risks of Digging and Excavation
Construction site managers must have strategies in place for mitigating the known risks of digging and excavation. For instance, when workers are required to be in trenches with a depth of 20 feet or greater, there must be solutions for preventing cave-ins that have been professionally engineered.
Moreover, percussive equipment such as jackhammers and heavy diggers should always be kept away from trenched spaces. Extra weight and strong vibrations paired with loose, damp or greatly eroded soils are all factors that make working conditions extremely unsafe. Soils that are removed from excavated areas should also be kept a suitable distance away from trenches. The additional weight of recently excavated soil that’s piled at the side of a trench can cause its walls to collapse.
Before any trench is entered, these spaces should be carefully reviewed for stability. Moreover, any factors that have the potential to disrupt or degrade the integrity of existing trenches should be identified and addressed. Finally, all workers in and around excavated areas should always have on the proper personal protective equipment. This includes hard hats, special work boots and other gear that is specific to the challenges of the environment [source].
Although construction can be dangerous work, project managers have the responsibility of ensuring that all possible risks are identified and mitigated before sending laborers in. In recently excavated areas, diligence in ensuring job site safety can be life-saving. In and around trenched areas, special care in pre-construction surveys, planning and staging can effectively prevent dangerous cave-ins.