Tips for Backfilling Trenches

Tips for Backfilling Trenches

Trench backfilling is the process of putting soil back into a trench after excavation is complete. The purpose of this tactic is to prevent the trench from settling, shifting and eroding.

Though the importance of backfilling is clear, not everyone knows how to perform this process. Through this step-by-step guide, we'll discuss how to backfill a trench and provide tips to help you achieve the best results.

How to Backfill a Trench

If you're preparing to backfill a trench, there are various steps required to get the job done right. In addition to knowing the best techniques, you'll also need to gather numerous resources.

1. Choose a Trench Backfilling Method

There are four primary methods for backfilling trenches, each using different materials and equipment:

  • Filling: This strategy involves flowable fill, a concrete material with a low water-to-cement ratio, that is delivered into the trench by a mix truck. 
  • Compacting: After soil is returned to the trench, it is condensed using compaction equipment. 
  • Dumping: The dumping method involves filling the trench with granular aggregate without compacting it.
  • Jetting: Water jetting is the process of spraying pressurized water into the trench to compact the soil.

2. Select a Backfill Type

Once you've chosen your trench backfilling method, you can select your backfill type. The material you require may depend on which method you chose in the previous step.

The four primary types of backfill include:

  • Uncompacted soil: This backfill refers to whatever soil is present on the job site, which is moved back into the trench without compaction. Though this is the cheapest option, it will likely require re-grading later. 
  • Compacted soil: Compacted soil backfill comprises job site materials that are packed into the trench.
  • Compacted stone: This option entails compacted granular backfill, which is best suited for areas that require paving. 
  • Lean concrete: Also known as controlled density fill, this material fills the trench without the need for secondary compaction. This backfill is typically useful for narrow or heavily trafficked areas.

3. Obtain Compaction Equipment

Securing the proper equipment for your backfilling project is crucial to delivering the highest-quality results. There are several types of compaction equipment you can use for your trench:

  • Rammers: Rammers deliver high impact force to compact soil using an engine-powered piston and springs, ridding it of any water or air. These devices are ideal for compacting cohesive materials like clay. 
  • Plate compactors: These machines deliver low-amplitude, high-frequency compaction to the ground by producing vibrations. Plate compactors are excellent for navigating tight spaces due to their ability to change direction. 
  • Trench rollers: Trench rollers are light, diesel- or gasoline-powered tools designed to compact soil in narrow areas. These machines come in ride-on and walk-behind models.
  • Compactors: Compactors are powerful machines designed to take on any compaction operation. There are several types of compactors, such as soil compactors, pneumatic rollers and landfill compactors.

4. Begin Backfilling

Once you've rounded up all of your equipment and materials, you can begin backfilling your trench. We recommend the compaction method, which delivers stable, long-lasting results. We'll delve deeper into this technique step by step to help you get started:

  1. Move your soil into the trench and spread it in an even layer 6 inches high.
  2. Pack the soil down using your compaction equipment. 
  3. Continue filling the trench with 6-inch soil layers and compacting it until the trench is full.

Tips for Backfilling Trenches Using a Wheel Loader

Wheel loaders are powerful, high-performance machines ideal for backfilling applications. You can perfect the trench backfilling process by adhering to the following tips:

  • Approach perpendicular to the trench to prevent your front tire from collapsing the trench wall or damaging the piping by applying too much pressure.
  • You can leave soil in the loader's bucket and use the bucket like a dozer blade to push the material into the trench rather than dumping it. 
  • Try working at an angle once the trench has been partially backfilled, keeping the tire closest to the trench on the backfilled side. This method prevents you from having to drive fully into the trench, as any dirt that's been left behind will fall into it on the next push.
  • If your excavated material piles are too high, you can build a ramp by rolling the soil and pushing it into the trench.
  • Be sure to avoid deflecting the objects being backfilled, such as pipes or manholes.

Rent Backfilling Equipment at The Cat® Rental Store

You can find a comprehensive selection of rental equipment for your next trench backfilling project at The Cat® Rental Store. We're proud to provide our customers with dependable, cost-effective machines supported by the latest technology.

Learn more about our equipment and get a quote by calling 1-800-RENT-CAT or browsing our extensive inventory today!

Find The Cat Rental Store Near You