The question “How deep does a vibratory rammer compact?” is as important for construction professionals as it is for DIYers. This is because only a robust, compacted ground guarantees the necessary load-bearing capability for paved areas, foundations, and excavations. In this article, you will discover the depth to which a modern vibratory rammer takes effect, the factors that influence compaction, and where the machines can best be used.

The compaction depth describes the area within the soil in which the vibratory rammer has a measurable impact on increasing the density. Important: This does not concern how far the machine “sinks,” but the depth at which the air and water is displaced and the pore space is closed.

The depth is dependent on different factors, including, amongst others, the weight of the vibratory rammer, the impact energy, the particulars of the soil, the water content, and the lift height. In practice, vibratory rammers typically compact between 3 and 7 cm per cycle. That means:

• A “pass” is a run across the same area.
• 2–3 runs are sufficient to achieve almost complete compaction (up to 100% Proctor density).

For greater depths, a single rammer run is inadequate. For that reason, layer compaction is utilized:

• A layer of approx. 20 cm is applied.
• This layer is compacted with several rammer cycles.
• Then the next layer is up.

With this procedure, it is possible to have sturdy backfillings of 40 cm and more.

Vibratory rammers are particularly efficient for:

• Cohesive soils (loam, clay)
• Mixed-grain soils (silty sand, gravel-clay-mix)

Pure sand layers or coarse-grain materials are less suitable and often where vibratory plates are more effective.

Vibratory rammers are above all practical where larger machines, such as vibratory plates, can't be used. Typical areas of application are:

• Trenches and construction site backfilling
• Border areas of pathways
• Repair areas in road construction
• Foundations of smaller structures

1. Soil layers too thick: If more than 20 cm is applied, compaction does not reach the lower areas.
2. Too few passes: Just one pass is normally not enough.
3. Incorrect soil type: Vibratory rammers are not ideal for every type of soil.

 

Here you will find an overview of all Wacker Neuson vibratory rammers.

1. How many passes are required with a vibratory rammer?
2-3 passes are generally enough to completely compact a layer.

2. Can you compact any ground depth with a vibratory rammer?
No, only 3–7 cm are effectively compacted with each pass. For greater depths, it is necessary to work in layers.

3. Is a vibratory rammer also suitable for sand?
Conditionally. Vibratory plates are normally better suited for loose sand.

4. How thick can a soil layer be before using the vibratory rammer?
Max. 20 cm are recommended per layer.

5. How do you recognize that the soil is adequately compacted?
When inspecting the area, it barely yields and shows no further settlements.

6. Which machine is better for paving works?
Vibratory plates are better suited for larger paved areas, vibratory rammers for border areas.

7. Can you over-compact the ground?
Yes, this can happen. If the soil is compacted for too long or with too much energy, the soil structure can be destroyed. The soil becomes too dense, it loses its elasticity, and water can no longer seep through, but it sits on the surface. Cohesive soils are particularly sensitive. It is therefore important to always compact in layers and to the required compaction grade.