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Diaphragm Wall Calculator

Panels, concrete, slurry and reinforcement for a deep-excavation wall.

Quick answer

With the default inputs: Wall length 100 m · Wall depth 25 m · Wall thickness 800 mm etc.Concrete volume 2160.0 m³

Use your own dimensions ↓

Inputs

Grab width per bite, usually 2.5-8 m
%

Result

Concrete volume
2160.0m³
Number of panels17strips
Actual panel length5.88m
Net volume2000.0m³
Support slurry3240m³
Reinforcement172800kg
Tonnes172.8t
How this is worked out

A diaphragm wall is built panel by panel; panel count is wall length ÷ panel length rounded up, and the last panel runs short. Concrete is placed underwater by tremie, so waste runs higher than normal (tremie carry-up and over-pour) - start at 8%. Bentonite slurry keeps the trench open through excavation and concreting, at about 1.5× the trench volume. The 80 kg/m³ reinforcement is an experience figure (double cages with heavier joint reinforcement); use the placing drawing for a firm number. Joint type (stop-end tube, H-section, cutter joint) moves cost materially and is not included here.

Next up: High Strength Bolt Torque Calculator · Plaster and Render Calculator

Formula

Panel countn = ⌈length ÷ panel length⌉
ConcreteV = length × depth × thickness × (1 + waste)
Slurry≈ concrete × 1.5
Reinforcement≈ concrete × 80 kg/m³
A 100 m wall, 25 m deep and 800 mm thick, 6 m panels, 8% waste: 17 panels, 2000 m³ net, 2160 m³ with waste, about 3240 m³ of slurry and 172.8 t of reinforcement.

How to work it out

  1. Panels = ⌈wall length ÷ panel length⌉, panel length set by the grab width (usually 2.5-8 m).
  2. Concrete = length × depth × thickness × (1+waste); thickness 600/800/1000/1200 mm by retention and cut-off needs.
  3. Support slurry is about 1.5× the trench volume, fed continuously and topped up or the trench collapses.
  4. Reinforcement is about 80 kg/m³, built in sections and lifted whole with lifting points to prevent distortion.
  5. Panel joints (stop-end tube or joint box) must be cleaned and sealed - the joint is the leak weak point.

Where it goes wrong

Material and cost

A diaphragm wall costs a lot per metre (grab rig, slurry circuit, cage, tremie concrete in one chain) - the heavy-asset one-stop retention-plus-cut-off for deep pits, used only when tight against the red line, deep, or near sensitive neighbours.

On site

Basis

FAQ

Diaphragm wall or soldier piles?
Depends on depth, surroundings and cost. A diaphragm wall is stiff, watertight and can double as the basement wall (top-down), suiting deep pits, sites tight against buildings or metro, and top-down construction - but it is costly and needs a grab and a slurry plant. Soldier piles with jet-grout cut-off are cheaper and simpler for moderate depth on less sensitive sites. High water table, deep soft clay or tight settlement limits point to a diaphragm wall.
Why can a panel not be too long?
Both the grab width and trench stability cap it. A grab bites a limited width (usually 2.5-8 m), and the longer the panel the harder the slurry has to work to keep the trench open before it collapses. Panels are kept short in soft and sandy ground, so panels are sized as a few bites each, keeping every panel excavated and concreted before the slurry loses the trench.

Cite this page

Use this format in reports, method statements or coursework. The link is permanent.

Building Calculator. Diaphragm Wall Calculator. 2026-10-25. https://jianzhujisuan.com/en/diaphragm-wall

Results are estimating aids only and are not a design basis. Construction and final accounts must follow the drawings, the applicable standards and an approved method statement. Anything affecting structural safety, shoring or falsework must be checked by a suitably qualified engineer.