# Jet Grouting Calculator Column volume and cement for jet-grout piles in one go. - Page: https://jianzhujisuan.com/en/jet-grout-pile - Category: Construction (https://jianzhujisuan.com/en/c/construction) - Chinese version: https://jianzhujisuan.com/zh/jet-grout-pile.md - Data checked: 2026-10-25 ## Quick result With the default inputs (Column diameter 600 mm, Column length 15 m, Number of columns 40 pcs, Cement content 350 kg/m³): **Cement 59.4 t** ## Inputs | Parameter | Type | Default | Unit | Note | |---|---|---|---|---| | Column diameter | select | 600 mm | — | | | Column length | number | 15 | m | | | Number of columns | number | 40 | pcs | | | Cement content | number | 350 | kg/m³ | Usually 300-400, higher in soft soil | ## Formula - **Volume per column**: V₁ = πD²/4·L - **Total volume**: V = V₁·n - **Cement**: M = V·content / 1000 (t) ## Worked example Φ600 × 15 m, 40 columns, 350 kg/m³: 4.24 m³ per column, ~170 m³ total, ~59.4 t cement. ### Quantities per metre by diameter (from this page's formulas, 350 kg/m³ cement) | Diameter (mm) | Section area (m²) | Volume (m³/m) | Cement (kg/m) | 15 m column (t) | |---|---|---|---|---| | 600 | 0.283 | 0.283 | 99 | 1.48 | | 800 | 0.503 | 0.503 | 176 | 2.64 | | 1000 | 0.785 | 0.785 | 275 | 4.12 | | 1200 | 1.131 | 1.131 | 396 | 5.94 | ### Single, double and triple fluid: what changes | Method | Column diameter (mm) | Jet medium | Typical pressure (MPa) | Typical depth (m) | Character | |---|---|---|---|---|---| | Single fluid | 400-600 | Cement grout | 20-30 | up to 20 | Simplest; small diameter, uniformity depends on the withdrawal rate | | Double fluid | 600-800 | Grout + compressed air | 20-30 | up to 25 | The air shroud extends the jet, one size larger | | Triple fluid | 800-1200 | Water, air and grout separately | water 30-40 | up to 30 | High-pressure water cuts first, grout replaces it: largest diameter, most return flow | ## Questions ### What cement content should I use? By soil and purpose. Regular cut-off and ground improvement use 300-350 kg/m³; soft soil or high strength takes 400 kg/m³ or more. Larger diameter and softer soil mean less complete replacement, so content goes up. Run a trial column first, measure the actual diameter and strength, then set parameters - do not commit volume on a rule of thumb. ### Can jet-grout columns form a cut-off wall? Yes, but they must interlock - adjacent columns need 150-250 mm overlap to seal, or the gaps leak. Column diameter varies strongly with soil (sand and gravel especially), so when using jet grouting for a cut-off wall the overlap and trial-column verification matter most; never assume the theoretical diameter. ### Jet grouting or deep mixing - which one? Judge by soil, depth and site access. Deep mixing (including the SMW method) gives uniform columns cheaply in mud, silty clay and clay, and is most economical to about 15 m; in sand, gravel, cobbles or obstructions, or beyond roughly 15-20 m, the mixing head cannot cut properly and both diameter and overlap become unreliable, which is where jet grouting takes over. Jet grouting costs clearly more and produces heavy return spoil needing a settlement pond and disposal, so use deep mixing for large cut-off walls and jet grouting for local strengthening, tight sites, congested services or restricted headroom. Pick wrong and the column either cannot be formed or the money is wasted. ### Jet grouting or soil mixing? Three things decide it: whether the rig can get in, how big a column you need, and what the ground is. Soil mixing (triple-axis) gives a more uniform column at a lower unit rate, but the rig is tall, needs a wide working platform and will not penetrate hard layers or cobbles. A jet grout rig is compact, works in confined space, hard against existing structures and inside basements, and will cut hard layers - but the unit rate is much higher and the return flow is heavy. So: soil mixing for bulk cut-off, jet grouting for local repair, tight corners and hard ground. ### How do I account for the return flow, and can it eat my margin? It can, and it is the most commonly missed item. Jet grouting replaces soil: the high-pressure grout cuts the ground and a soil-grout mix comes back out of the hole. The volume is broadly the same order as the column volume, though it varies widely with ground and method, so measure it on site rather than assuming. It costs twice: haulage and disposal of the return flow, plus the grout lost with it. If you price grout as column volume times cement content and forget disposal, disposal comes straight out of your margin. ### How is the column diameter fixed - can I just take it off the drawing? The drawing gives the required column diameter. What you actually achieve depends on the ground, the pressure, the withdrawal rate and the nozzle. The same nozzle can differ by more than 30% between soils: sand over-cuts, clay and dense silt under-cut. So the order is: trial column first, measure the real diameter, then fix the cement content and the count. Taking the drawing diameter straight into a cement calculation normally comes out short. ### Why is jet grouting so much more expensive than soil mixing? Three reasons. Cement content is higher - 300-400 kg/m³ of column is normal, against the equivalent of 15-20% by soil weight for soil mixing. The return flow has to be hauled and disposed of, which is pure additional cost. And output is low: the withdrawal is slow, so fewer cubic metres per shift. That is why jet grouting is used where soil mixing cannot go - confined space, hard layers, hard against existing structures, local leak repair. Using it across a whole site puts the cost a tier above soil mixing. ## Related tools - [Plaster and Render Calculator](https://jianzhujisuan.com/en/plaster-coat): Mortar, cement and sand by layer for internal plastering. - [Mortar Mix Design Calculator](https://jianzhujisuan.com/en/mortar-strength): Trial strength, cement, water and sand, and the mix by mass. - [Labour Days and Crew Calculator](https://jianzhujisuan.com/en/labor-productivity): Man-days, crew size and labour cost from output rates. - [Line-of-Balance Duration Calculator](https://jianzhujisuan.com/en/schedule-flow): Rhythmic flow duration with overlap and break adjustments. - [Material Storage Area Calculator](https://jianzhujisuan.com/en/material-storage): Net footprint, total area and a suggested bay size. - [Dewatering Calculator](https://jianzhujisuan.com/en/dewatering): Pit inflow by the equivalent-well method, then well count. --- Generated by BuildCalc. All calculations run in your browser; no data is uploaded. Formulas follow national standards and common trade practice; local codes govern.