1 General Provisions
1.0.1 This standard is formulated to unify soil engineering classification and the qualitative evaluation on the soil properties.
1.0.2 This standard is applicable to basic classification of the soil. By complying with this standard, this industry may prepare the classified standard according to the need.
1.0.3 Soil classification parameter test shall, besides meeting the requirements this standard, comply with the requirements in the current relevant standards of the nation.
2 Terms, symbol and code
2.1 Terms
2.1.1 Grain size
Soil particle can pass through the minimum sieve mesh or the diameter of the soil particle is same to that of the equivalent sphere with same sink rate.
2.1.2 Grain size distribution curve
Relation curve showing the percentage of the grain size of soil particle of the total.
2.1.3 Constrained grain size
On the grain size distribution curve, the quality of soil particle smaller than this grain size account for 60% of the total mass.
2.1.4 Effective grain size
On the grain size distribution curve, the quality of soil particle smaller than this grain size account for 10% of the total mass.
2.1.5 Fraction
Groups set divided according to grain size.
2.1.6 Coefficient of uniformity
Soil particle size distribution homogeneity coefficient
2.1.7 Coefficient of curvature
Coefficient of grain size distribution curve form of soil particle.
2.1.8 Gradation
Ratio of all fraction in the total soil particle mass.
2.1.9 Liquid limit
Limit water content between flow regime and plastic state.
2.1.10 Plastic limit
Limit water content between plastic state and semisolid status
2.1.11 Plasticity index
Difference between liquid limit and plastic limit.
2.1.12 Plasticity chart
Fine particle soil classification figure with plasticity index IP as longitudinal coordinate and liquid limit Wl as lateral coordinate.
2.1.13 Organic soil
Ball clay or silty soil with certain organic content Om (5%≤Om <10%), characteristic odor and high compressibility.
2.1.14 Organo-soil
Ball clay or silty soil with certain organic content Om (Om ≥10%), characteristic odor and high compressibility.
GB/T 50145-2007 The following standards are cited：
