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STANDARD 18-1 1997 UNIFORM BUtLDtNG CODE
<br /> sification. Exatnpie: A gravel with 10 percent fines, a Cr. of 20, a present insufficient amounts to influence the soil properties, then''
<br /> Cz of 2.0, and a plasticity index of 6 would be classified as tentatively classify We soil as organic silt or clay, O.
<br /> GW-GM rather than GW GC.) If the soil has a dark color and an organic odor when moist and ,
<br /> warm, a second liquid limit test should be performed oa a test sam-
<br /> SECTION i 8.107 - FtROCEDURE FOR ple which has been oven dried at 110°C f ~°C for 24 hours.
<br /> CLASSIFICATION OF FlNE-GRAINED SOILS (~assify the soil as organic silt or day, O, if the liquid limit after
<br /> (50 PERCENT OR MORE PASSING) ovtn drying is less than Wree fourths of the liquid limit of the origi-
<br /> From the material passing the 3-inch (76 mm) sieve, select a test nest sample determined before drying.
<br /> sample for the determination of the liquid limit and plasticity in- ~~Y ~ soil as inorganic silt of low plasticity, ML, or as or-
<br /> der. The method for wet preparation shall tie used for soils con- t;~ ~ of bw.plastiaty, ML; tx as tKganic sift or silt-day of low
<br /> raining organic matter or irreversible mineral colloids. Qlasticity, OL, if the liquid limit is less Wan 50 and the plot of liq-
<br /> nid limit versus plasticity ibex falls bebw the "A" line or the
<br /> Determine the liquid limit and the plastidty index of a portion plasticity index is less than 4. See area identified as ML and OL on
<br /> of the test sample passing the No..40 (425 µm) sieves the plasticity Chart, Table 18-i-A
<br /> Classify the soil as inorganic clay, C, if the plot of liquid limit pass ffy We soil as inorganic silt of medium to high plasticity,
<br /> versus.plasticity index falls above We "A" line and the plasticity MH, or as organic clay or siit~;lay of meditun to high plasticity,
<br /> index ~ than OH, if We liquid limit is more Wan SO and We plot of liquid limit
<br /> (aassify the soil as inorganic clay of low to medium plastitty, . versits plastidty index falls below the "A"line. See area identified
<br /> GL, if the liquid limit is less than 50 and the plot of liquid limit vcr- ~ MH and OH on the Plasticity Chart of Table 18-1-A
<br /> sus plasticity index falls above We "A" line and We plasticity in- In order to indicate their borderline characteristics, some
<br /> der is greater than 7. See area identified as CL on the Plasticity fine-grained soils should be classified by dual symbols.
<br /> Chart of Table 18-1-A. If the plot of liquid limit versus plasticity index falls on or prac-
<br /> Cfassify We soil.as inorganic day of high plasticity, CH, if We tically on the "A" line or above the "A" lino where We plasticity
<br /> liquid limit is greater Wan 50 and We plot of liquid limit versus index is in the range of 4 to 7, the so$ should be given an appropti-
<br /> plasticity index falls above We "A"line. In caws where We liquid ate borderline classification such as CIrML or CH-0H.
<br /> limit exceeds 100 or the plasticity index exceeds ti0, We plasticity If We plot of liquid limit versus plasticity index falls on or prat- -
<br /> drart may be expanded by maintaining We same scales on b°th acally on the line ligtad limit = S0, the soil should be given an ap-
<br /> axes and extending the "A" line at We indicated slope. See areas
<br /> identified as CH on the Plasticity Chart, Table 18-1-A. ProP~~ bo~~line classification such as (~.-CH or ML-MH. (In
<br /> doubtful t~scs the rule for classification is to favor the more plas-
<br /> Classify We soil as inorganic silt, M, if the plot of liquid limit tic classification. Example: a fiaagraincd soil with a liquid lirpit
<br /> versus plasticity index falls below the "A" line or if the plasticity of 50 and a plasticity index of ?2 would be classified as CH-MH
<br /> index is less than 4, unless it is suspected that organic matter is rather than GUML.)
<br /> TABLE 18-1-A~SOIL CI.ASSIFiCAT10N CHART
<br /> • tmour
<br /> Mn.lon avtsloas srMeas Twlcu NnatFs
<br /> GW Wetl-graded gravels and gnvet-sand mixtures, little or no fins
<br /> cwtvas cw?vas
<br /> sox a«~ GP Poorly loaded gtaavels and gavel-sand mixtures, little or no fines
<br /> GRAR/ED warned on No. a µrs rap stay. GRAVELS GM Silty gpvels, gravel-sand-silt mixtures'
<br /> sous wtitt RNES. lie Clayey gavrls, stave!-aatia~lay m;xturea
<br /> Mon flan sox a.Enat Sw ~VEit-gaded scads and gravelly scads, little or no Goes
<br /> ~s~ bore ttan ~
<br /> oil SANDS SP Poody gaded scads and gravelly and sands, tittle or no fins
<br /> wsss tto. 4 N-7s akae SANDS SM Silty scads, sand-silt mixtures
<br /> rvtitt SC Clayey sands, ssod-stay mixtures
<br /> ~ In~ is st7ts, very Sae sands, rock tlou ,silty. or clayey fine
<br /> sacs ANO CIAYs
<br /> ~ ~ sox Inorganic days of low to medium plasticity, gravelly clays, sandy
<br /> FlNE~RAUrtEn sops Q" clays, silty days, lean days .
<br /> sox «mon passes OL Organic Gilts and organic silty days of low plasticity
<br /> tVa s~reva~ P+N MH la0rgaaic silts, micaceous a diatomaceous fine sands or silts,
<br /> sans nrto torts clastic s?'!ts
<br /> ~++s amlt 9`"at°`ti'a" sox CH inorganic days of high plauidty, fat days
<br /> OH Organic days of medium to high plasticity
<br /> NAY oi9snte Salmi PT Peat, muck and other highly organic soils
<br />
<br /> rliased oa the material passing the 3-inefi (76 mm) sieve.
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