June 23, 2015
Edward Smith

Precautions Against Danger Of Trench Collapse

Construction workers have a difficult job and are exposed to risks daily while on the job.
Excavation worker’s in particular have a peculiar risk of harm.  When they are working below ground level and involved in excavating trenches, there is always the danger of a trench collapse. To protect against risks, workers much be trained on how and why accidents occur on job sites.  They must also be taught what can be done ahead of time to take precautions against trench failure.  Various methods exist to eliminate and reduce the risk of injury by trench collapse.

Education And Training Of Construction Workers

Experience has found that education and training of workers prior to undertaking work on a job site goes a long way to prevent injuries caused by trench failure.
OSHA regulations require that, among other things, workers need to be trained on are: 1) the types of soil; 2) the weights of soils; 3) the moisture content of soil and height of the surrounding water table; 4) Changes in weather, and the effects of and thawing of soil; 5) the effect of vibrations and/or weight from vehicles and adjoining structures.

Construction workers need to be educated on these subjects so that they recognize the conditions they are working in and take the appropriate steps to ensure that they are doing the job properly and protecting themselves from risk of serious harm. The risk of a trench collapse goes up when the soil is less stable and dense, if it is affected by weather, there is interference from adjoining forces.

Soil Inspection And Testing

Types of Soil are categorized according to stability in decreasing order, ranging from rock, to Type A, Type B and Type C. These are generally rock, clay or sandy clay, gravel, silt and sandy loam; and last, “farmer’s dirt.” A qualified or “competent” person must do a visual and or manual test to determine what type of soil is being worked on and how long it will “stand up” under its own weight.

Because conditions change during the course of the work day, the qualified individual needs to do the inspection not only at the start of the shift but periodically during the course of the day to see if any changes have occurred. In doing a visual test it is important to be on the lookout for cracks that may have developed in the soil or on the walls; evidence of prior excavation; if there are any sources of vibration near at hand; if there is any water coming in from the surrounding area.

The test can be done manually using a Plasticity test.  A sample of dirt can be rolled into a ball and then into the shape of a dirt snake.  A piece can be broken off to guage how solid it is. The solidity can also be tested by and a thumb penetration test. These tests determine whether the soil stays to together or crumbles easily. There are also two tests that can be done with instruments, the Pocket Penetrometer and Shearvane tests. All these tests are done to find out the stability of the soil and minimize risk of trench collapse.

Protecting Against Trench Cave-Ins & Collapses

There are various ways to prevent trench cave- ins and collapses.

Trench collapse occurs usually when the surrounding support of the wall is removed or impaired. In order to prevent this from happening, OSHA requires that workers be additionally trained in protective systems.  These typically involve “sloping” or “benching” the trench.

First, the relative stability of the soil must be determined.  Then,  a slope or bench can be added to the trench to level it out and minimize or totally prevent the risk of a collapse. The more stable the soil, the smaller degree of slope or size of benching. The less stable the soil, more of  a slope or benching is reOSHA has various regulations for trenches over four feet in depth.

If the trench is over four feet, there must a ladder or ramp with some form of access or exit located within 25 feet of the worker. Further, when shoring or benching are not practical on the site, the site must use shoring or shielding methods to guard against collapse. Shoring usually involves metal or timber uprights, sheet piling or other methods. Shield protects workers from cave ins in a specific area but is not necessarily designed to prevent trench collapse. Shoring might involve using a portable trench box that is moved along the site as work progress.

Any excavation using a shielding or shoring system must keep a copy of the manufacturer’s and technical information of site, as well of inspection records.

Understanding The Cause Of Trench Collapses

Despite the best efforts of companies, managers, and workers, construction accidents happen from time to time. When a trench collapse occurs, it can not only result in delay of completion of the job.  It can also result in serious injury or even death for the construction worker. When such cases occur, it is important to review the training provided to the employees regarding soil conditions and causes of trench failure. It would also be necessary to determine the nature and extent of any soil test and evaluation made by the qualified or competent person. Any methods or systems using shoring or shielding methods would have to be properly evaluated to determine if the proper method was selected and implemented.

In order to evaluate the consequences of an accident involving a trench collapse or cave-in, it is extremely helpful to have an experienced personal injury lawyer on your side. Catastrophic Injury Attorney Edward A Smith has been practicing personal injury law for over 30 years. Hiring an attorney that has the highest level of knowledge, skill and expertise resources can make a huge difference in the outcome of your case.
If you or a loved one have suffered from a catastrophic injury, contact the experienced Catastrophic Injury Attorneys at the Edward A Smith Law Offices for a free consultation at (916) 921-6400 or toll free at 1-800-404-5400, Reviews of our office can be found on YELP and AVVO.