Admin Order 58-02-25-F (2) - Laserfiche WebLink

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STANDARD 18-4 sification. Example: A gravel with 10 percent fines, a Cu of 20, a. Cz of 2.0, and a plasticity index of 6 would be classified as GW-GM rather than GW-GC.) SECTION i8.it)7-PROCEDURE FOR CLASSIFICATION OF FINE-GRAINED SOILS (50 PERCENT OR MORE PASSING) From the material passing the 3-inch (76 mm) sieve, select a test sample for the determination of the liquid limit and plasticity in- dex. The method' for wet preparation shall be used for soils con- taining organic matter or irreversible mineral colloids. Determine the liquid limit and the plasticity index ~of a portion of the test sample passing the No..40 (425 µm) sieve. Classify the soil as. inorganic clay, C, if the plot of liquid limit versus.plasticity index falls above the "A"line and the plasticity index is greater than 7. Classify the soil as inorganic clay of !ow to medium plasticity, CL, if the liquid limit is less than 50 and the plot of liquid limit ver- sus plasticity .index falls above the "A" line and the plasticity in- dex is greater than 7. See area identified as CL on the Plasticity Chart of Table 18-i-A. Classify the soil.as inorganic clay of high plasticity, CTI, if the liquid limit is greater than SO and the plot of liquid limit.versus plasticity index falls above the "A" line. In cases where the liquid limit exceeds 100 or the plasticity index exceeds 60, the plasticity chart'may be expanded by maintaining the same scales on both axes and extending the "A" line at the indicated slope. See areas identified as CH on the Plasticity Chart, Table 18-1-A. Classify the soil as inorganic silt, M, if the plot of liquid limit versus plasticity index falls below the "A"line or if the plasticity index is less than 4, unless it is suspected Wat organic matter is ---o ..._ ..,., ~........~ ~.~.~. 1997 UNIFORM BUILDING CODE present insufficient amounts to influence the soil properties, then ``~''~'- tentatively classify the soil as organic silt or clay, O, If the soil has a dark color and an organic odor when moist and .~ warm, a second Liquid limit test should be performed on a test sam- ple which has been oven dried at 110°C ± 5°C for 24 hours. Classify the soil as organic silt or clay, O, if the liquid limit after oven drying is less than three fourths of the liquid limit of the origi- nal sample determined before drying. Classify the soil as inorganic silt of low plasticity, ML, or as or- ganicsilt of low.plasticity, MI; or as organic silt or silt-clay of low plasticity, OL, if We liquid limit. is less than 50 and the plot of liq- uid limit versus plasticity index falls below the "A" line or the plasticity index is less than 4. See area identified as ML and OL on the Plasticity Chart, Table 18-1-A. Classify the soil as inorganic silt of medium to high plasticity, MH, or as organic clay or silt~lay of medium to high plasticity, OH, if the liquid limit is more than SO' and the plot of liquid limit versus plasticity index falls below the "A"lice. See area identified as MH and OH oa the Plasticity (hart of Table 18-1 A In order to indicate their borderline characteristics, some fine-grained soils should be classified by dual. symbols. Tf We plot of liquid limit versus plasticity index falls on or prat= tically on the "A" line or above the "A" line where the plasticity index is in We range of 4 to 7, the sor7 should be given an appropri- ate borderline classification such as CL-ML or CH-0H. If the plot of liquid limit versus plasticity index falls on or prat- ,-- - . tically on the line liquid limit = 50, the soil should be given an ap- propnateborderline classification such as CINCH or ML-MH. (In doubtful rases the rule for classification is to favor the more plas- tic classifcafion. Example: afire-grained soil with a liquid Iirpit of 50 and a plasticity index of 22 would be classified as CH-MH rather Wan CL-ML.) TABLE 18-1-A~OlL CLASSIFiCAT10N CHART