Sand Strata Construction Solution
A full material and process package from mix design to loss control, holding surface settlement under 3 mm in water-rich sand.
Solution overview
- Application methods
- 旋挖灌注桩施工 / 深基础施工 / 非开挖管线施工
- Problem type
- Strata
Scenario and construction challenges
Shield tunnelling and piled foundations in water-rich fine silty sand: high permeability causes severe slurry loss, so film-forming speed and settlement control must go hand in hand.
Challenge 1Heavy loss
High porosity in water-rich sand makes ordinary bentonite slurry lose heavily, driving up material consumption.
Challenge 2Slow film forming
Slurry that cannot film the wall quickly leaves poor protection and risks collapse.
Challenge 3Settlement sensitive
Tight surface settlement limits demand a stable pressure balance in the hole.
Complete solution
Each scheme pairs materials with dosing; the table below lists material, role and ratio per step.
| Stage | Material | Function | Ratio / dosage | Working condition | Scope |
|---|---|---|---|---|---|
| Make-up | PAM-S for sand | Film-forming main material | 1:400 | Water-rich fine sand, k = 10⁻³–10⁻² cm/s | Film-forming protection for rotary / shield bores |
| Concentrated section | PAM-S concentrated slurry | Reinforced wall through crossing | 1:250 | Crossing sections with loss >5 L/min | Cross passages and pipe-jacking crossings |
| Base slurry | BENT-N sodium bentonite | Base make-up | 8%–10% | Fresh-water make-up, 5–35 °C | Base slurry used with PAM-S |
| Viscosity tune | CMC-N viscosifier | Cuttings carry & viscosity | 0.3% | Return slurry losing viscosity or carry | Sand-stratum circulation maintenance |
Delivered results
Construction schematic & site photos
Use the schematic and site photos to follow the process and slurry flow; final parameters follow on-site trial results.
Construction schematic
Site photos
Related cases
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