Subsea Soft Ground Replacement Method

1. Method Overview

1) Ground improvement method that creates large-diameter compacted sand columns on the soft ground of the seabed. 2) Improvement effects

  ① Sandy soil

   - Prevents liquefaction during earthquakes and ground motions

   - Increases horizontal load (increases shear strength)

   - Reduces compressive settlement

   - Homogenization of the ground by compaction

  ② Clayey soil

   - Increases shear resistance and bearing capacity by forming a composite ground

   - Prevents sliding destruction

   - Shortens consolidation time and reduces consolidation settlement (DRAIN effect)

   - Prevents uneven settlement with the composite ground function

3) Applicability

   Applicable to almost all grounds such as sandy soil, clayey soil, organic soil, rocky soil (landfill), and sedimentary soil

2. Construction method features

1) Compaction, reinforcement, and drainage promotion

2) Increases shear strength

3) Prevents liquefaction

4) Shortens air time

5) Increases bearing capacity

3. Construction method and sequence

1) Fixing the location

2) CASING penetration: Automatic air control device operation 3) CASING pull-out

4) CASING compaction

5) When compaction is complete, pull-out as in method 3)

6) Work as in method 4)

7) Repeat methods 3), 4), 5), and 6) from the support layer to the ground surface (planned depth).

8) Work completion