ISKRIT / Site investigation & geotechnics / Grain-size distribution · USCS
Site investigation & geotechnics
Grain size distribution and USCS classification: d10, d60, Cu
From sieve and hydrometer analysis the tool plots the particle size distribution curve, finds the controlling diameters, and classifies sands and coarse-grained soils.
Data current as of 2026-08-24
Standards
USCS (ASTM D2487) and EN ISO 14688-1: group symbol from the grain size distribution and plasticity, Cu = d60/d10, Cc = d30²/(d10·d60).
Input
Percent passing or partial masses retained in grams per sieve; computed in the browser.
Output
Curve, d10/d30/d60, Cu, Cc, soil name.
What it does
- Particle size distribution curve
- Controlling diameters d10, d30, d60
- Coefficient of uniformity Cu and curvature Cc
- Naming under USCS (ASTM D2487) and EN ISO 14688-1
The tool and the platform
The tool
- Grading curve, d10, d30, d60, Cu, Cc and the soil name
- Load the sieve table from Excel, export to XLSX, print the curve
- Calculations are stored on the server and reopen next time, company letterhead with signatures
- Works instantly, no sign-up required
ISKRIT·Geo demo
The work of a whole department: roles, history and modules linked together.
- Curves are kept with the site samples and roll up into one schedule
- The classification goes into the unit name automatically
- Batch AGS4 import instead of pasting one sample at a time
Questions
Which analyses are supported?
Sieve analysis for sands and coarse soils, hydrometer analysis for fine fractions.
How is uniformity assessed?
Cu = d60/d10; soil with Cu below 3 is classed as uniform.