Distinctive feature
Suppress sedimentation and prevent ground collapse
When excavating collapsible natural ground with low fine particle content using slurry type pipe jacking method/slurry shield method, stopping the slurry circulation may cause soil particles in the slurry to settle, resulting in a decrease in the specific gravity of the slurry water in the upper part of the chamber. If such a situation occurs, groundwater may flow into the chamber, causing the ground at the cutting face to loosen and increasing the risk of collapse.
Kiriha Hokai Boshizai suppresses sedimentation of soil and stabilizes the cutting face, preventing such on-site issues.
Ⅰ. Previous problems
When the cutter is stopped, the soil in the chamber settles, causing groundwater to flow in and the natural ground to collapse.
Ⅱ. When using Kiriha Hokai Boshizai
After stopping the cutter, inject Kiriha Hokai Boshizai into the chamber and rotate the cutter to mix it with the slurry, thereby preventing the collapse of the natural ground.
Application site
Slurry Shield Method
Packaging Type
| Main agent | Auxiliary agent | |
|---|---|---|
| Net Weight | 6 kg | 20 kg |
| Package Style | Poly Can | Steel Can |
How to use
- Follow the formulation table below and add the main agent into the tank. Next, send the auxiliary agent into the tank and stir it with a hand mixer inside the tank. After that, inject the mixed solution into the chamber using a pump.
- After injecting the mixed solution in step 1, inject the auxiliary agent into the pipes to clean them.
| Main agent solution | Auxiliary agent solution | |
|---|---|---|
| Mixing ratio per 1m³ of chamber |
0.3～1.2 L | 19.7～18.8 L |
| 20 L | ||
*Please conduct a table test before use.
＜Construction Illustration＞
Major construction projects
＃1
| Pipe diameter | φ3,000mm |
|---|---|
| Extension | L460ｍ |
| Soil type |
Sand layer (with fine particle content of 6.5% or less) |
| Construction method | Slurry type pipe jacking method |
Kiriha Hokai Boshizai is injected for each jacking pipe.
Despite the highly collapsible soil, no ground subsidence occurred, and the target was successfully reached.
In the future, it is expected that there will be an increasing number of cases where cutting face collapse prevention measures are included in the design documents for collapsible ground, such as near coastlines.