Soil Improvement Techniques in Excavation Support
Soil improvement in excavation support using preloading is a technique applied before construction begins on soils that require significant consolidation settlement.
Once the ground has sufficiently consolidated, the applied preload can be removed, and construction can commence.
Applications of This Technique
In general, this technique is effective in clay soils. Since clay has low permeability, consolidation occurs slowly, even under large preloads.
Therefore, in projects where time is critical—such as buildings and deep excavations (retaining walls, nailing, anchoring, micropiles, top-down methods, etc.)—this technique alone is not sufficient. To accelerate the consolidation process, sand drains or vertical drains are often used to shorten drainage paths and reduce consolidation time.
Figure 1 shows an example of soil improvement by preloading.
