What is a consideration when backfilling a trench with difficult compostion?

Using gravel, a soil stabilizer, or a slurry mixture is important when backfilling a trench with a difficult composition because these materials help ensure stability and support for the surrounding soil. Difficult compositions may include soils that are overly loose, saturated, or prone to erosion, which can lead to issues like settling over time.

Gravel provides drainage and helps prevent water accumulation, which can contribute to soil instability. Soil stabilizers are used to enhance the cohesion and compaction of the existing soil, making it less susceptible to shifting or settling. A slurry mixture, often made of cement, water, and sometimes additional materials, can fill voids and solidify, providing a strong, stable support for the surrounding area.

In contrast, using organic material may decompose over time, leading to further settling issues. Relying solely on native soil does not take into account the specific challenges posed by the trench's composition. Filling with air is impractical and unrealistic, as it does not provide the necessary support or stability. The combination of gravel, stabilizers, and slurry addresses these concerns effectively, making it the preferred choice for backfilling in challenging conditions.