Boulder-strata pile walls in Northwest China: 98% wall stability
A bridge foundation in Northwest China crossed boulder beds. Large stones violently disturbed the walls — collapse and spalling were frequent, and heavy waste slurry forced constant pond clean-outs.
Project overview
- Region
- Northwest
- Project type
- Bridge piles
- Project scale
- Bridge piles through boulder beds with large stones and severe wall disturbance
Construction challenges
The main construction challenges encountered on this project.
Challenge 1Boulder disturbance
Grabbing boulders kept shocking the wall, making the protective layer hard to hold.
Challenge 2Collapse & spalling
Wall collapse and spalling were frequent, threatening hole quality and safety.
Challenge 3Heavy waste slurry
Large waste volumes forced frequent mud-pond clean-outs and disposal pressure.
Solution & materials
Materials and mix ratios used step by step on this project, for reference by similar works.
| Stage | Material | Function | Ratio / dosage |
|---|---|---|---|
| Make-up | PAM-P | High-carry main material | 1:200 |
| Thickening | CMC-N | Yield point & wall strength | 0.4% |
| Base slurry | BENT-N | Base make-up | 8% |
| Support | Percussion-rig slurry | Top-up with progress | As required |
Implementation notes
Switching to 1:200 PAM-P high-carry slurry with CMC-N strengthened the protective layer markedly. With top-ups tuned to percussion progress, collapse and spalling almost disappeared; better slurry reuse cut waste by 40% and wall stability reached 98%.
Delivered results
Site photos
Related products
NPT-CMC-N- High-viscosity grade
- Dissolves fast
- Low ash content
NPT-PAM-P- Good film encapsulation
- Strong scour resistance
- Low fluid loss keeps hole diameter
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