What is trench backfill?

Backfilling is the process of putting the soil back into a trench or foundation once excavation, and the related work has been completed. The backfill process requires skills and heavy equipment as well as knowledge of the specifications, contract requirements, and soil conditions.

What is the minimum trench width?

The minimum trench width shall be two (2) inches wider than the conduit being placed in the trench. The maximum rock wheel trench width shall be six (6) inches.

What is suitable backfill material?

Coarse-grained soil: This is standard backfill material in home construction. It contains sand, gravel, and small amounts of fine materials. This backfill provides ample support for your foundation and is easy to tamp down.

Can you backfill a trench with water in it?

Trench Compaction: Here, an excavator, a compactor, or some other mechanical means are used to compact loose material into the trench. Soil is backfilled in layers of four to six inches depending on the type of compaction equipment used and the nature of the backfill. Water may be added to help with the compaction.

How do you calculate trench backfill?

The volume of a rectangular cubed shape is found by the formula v = l x w x d, where v represents volume, l is the length of the trench, w is the width and d is the depth. Applying the numbers to this formula (8x 50x 6) the cubic footage of the example area is 2400 cubic feet.

What are the different backfill conditions?

Backfill materials can generally be graded as: Coarse grained soils – gravelly and sandy soils ranging from clay to gravel. Fine grained soils of low to medium plasticity – inorganic clays of low to medium plasticity, inorganic silts and very fine sands of low plasticity.

How wide should a trench be with a pipe?

The trench width at pipe grade should be equal to the pipe outer diameter plus 12 inches. Dewatering. For safe and proper construction the groundwater level in the trench should be kept below the pipe invert.

How do you measure trench width?

The trench width shall be measured at the top of the pipe barrel and shall conform to the following limits: 1. Minimum: Outside diameter of the pipe barrel plus 12 inches, i.e., 6 inches each side.

What are the types of backfill?

Different Types of Backfilling Material

  • Course Grained Soil. Coarse-grained soils include gravelly and sandy soils and range from clayey sands (SC) through the well-graded gravels of gravel-sand mixtures (GW) with little or no fines.
  • Fine Graded of Soils of Low to Medium Plasticity.
  • Commercial By-Products.
  • CLSM.

What is the thickness of the backfill layer?

Cohesive backfill shall be deposited in horizontal layers not exceeding 200 mm in thickness. Every layer shall be tamped in place and well compacted by means of mechanical tampers before the next layer is deposited.

How much back fill do I need?

What is the maximum width of a trench?

In general, the depth of a trench is greater than its width, but the width of a trench (measured at the bottom) is not greater than 15 feet (4.6 m).

What is the thickness of backfill layer?

How do you calculate filling quantity?

Suppose we need to fill the plot by 3’5” = 3.41 feet. So, the depth of the plot = 3.41 feet. Volume of plot to be filled = 1200 x 3.41 = 4092 cft.

What are the OSHA requirements for trenches?

OSHA requires employers to provide ladders, steps, ramps, or other safe means of egress for workers working in trench excavations 4 feet (1.22 meters) or deeper. The means of egress must be located so as not to require workers to travel more than 25 feet (7.62 meters) laterally within the trench.

At what depth does a trench require shoring?

five feet deep
Depth of trench If the trench is five feet deep or more it must be shored or sloped. If there is a possibility of soil movement, even shallower trenches have to be shored.

What is the acceptable percentage of compaction?

In general, a compaction between 80 and 85 percent of the standard Proctor maximum dry density optimizes slope stability with vegetation development and growth.

Can you reach more than 100% relative compaction?

Because conditions in the field do not match the ideal conditions in a laboratory, the target compaction is scaled to a percentage of the dry density determined in the lab. This can range from 90 percent to over 100 percent.