|
EXHIBIT D
<br />UNIFORM BUILDING CODE STANDARD 18-1
<br />SOILS CLASSIFICATION
<br />Based on Standard Method D 2487-69 of the American Society for Testing and Materials.
<br />Extracted, with permission, from the Annual Book of ASTM Standards, copyright American Society for
<br />Testing and Materials, 100 Barr Harbor Drive, West Conshohocken, PA 19428
<br />See Sections 18012 and 1803.1, Uniform Building Code
<br />
<br />SECTION 18.101 -SCOPE
<br />This standazd describes a system for classifying mineral'and or-
<br />ganomineral soils for engineering purposes based on laboratory
<br />determination of particle~rze characteristics, liquid limit and
<br />plasticity index.
<br />SECTION 18.102 -APPARATUS
<br />Apparatus of an approved type shall be used to perform the fol-
<br />Iowing tests and procedures: Preparation of soil samples, liquid
<br />limit test, plastic limit test and particle-size analysis.
<br />SECTION 18.103 - SAMPLING
<br />Sampling shall be conducted in accordance with approved meth-
<br />ods for soil investigation and sampling by auger borings, for Pene-
<br />tration Test and Split-barrel Sampling of Soils, and for
<br />Thin-walled Tube Sampling of Soils.
<br />The sample shall be carefully identified as to origin by a boring
<br />number and.sample number in conjunction with a job number, a
<br />geologic stratum, a pedooogic horizon or a location description
<br />with respect to a:permanent monument, a grid system or a station
<br />number and offset with respect to a stated center line.
<br />The sample should also be described in accordance"with an ap-
<br />proved visual-manual procedure. (A soil which is composed pri-
<br />marily of undecayed or partially decayed organic matter and has a
<br />fibrous texture, dark brown to black color, and organic odor
<br />should be designated as a highly organic soil, PT, and not sub-
<br />jected to the classification procedures described hereafter.)
<br />SECTION 18.104 -TEST SAMPLE
<br />Test samples shall represent that portion of the field sample finer
<br />than the 3-inch (76 mm) sieve and shall be obtained as follows:
<br />Air dry the field sample; weigh the field sample; and separate
<br />the field sample into two fractions on a 3-inch (76 mm) sieve.
<br />Weigh the fraction retained on the.3-inch (76 mm) sieve. Compute
<br />the•percentage of plus 3-inch (76 mm) material in the field sample
<br />and note this percentage as auxiliary information. Thoroughly
<br />mix'the fraction passing the 3-inch (76 mm) sieve and select test
<br />samples.
<br />SECTION 18.105 - PRELIMINARY CLASSIFICATION
<br />PROCEDURE
<br />Procedure for the.determination of percentage finer than the No.
<br />200 (75 µm) sieve is as follows:
<br />1. From the material passing tfie 3-inch (76 mm) sieve, select a
<br />test sample and determine the percentage of the test sample finer
<br />than the No. 200 (75 µm) sieve. ("This step may be omitted if the
<br />soil can obviously be classified as fine-grained by visual inspec-
<br />tion.)
<br />2. Classify the soil as coarse-grained if more than 50 percent of
<br />the test sample is retained on the No. 200 (75 µm) sieve.
<br />3. C~assify'the soil as fine-grained if 50 percent or more of the
<br />test sample passes.the No. 200 (75 µm) sieve.
<br />SECTION 18.106 -PROCEDURE FOR
<br />CLASSIFICATION OFCOARSE-GRAINED SOILS
<br />(MORE THAN 50 PERCENT RETAINED]
<br />Select test samples from the material passing the 3-inch (76 mm)
<br />sieve for the determination of particle-size characteristics, liquid
<br />limit and plasticity index. Detemtine the cumulative particle-size
<br />distribution of the fraction coarser than the No. 200 (75 µm) sieve.
<br />Classify the sample as gravel; G, if 50 percent or more of the
<br />coarse fraction [plus No. 200 (75 µm) sieve] is retained on the No.
<br />4 (4.75 mm) sieve. Classify the sample as sand S, if more than 50
<br />percent of the coarse fraction (plus No. 200 (75 µm) sieve] passes
<br />the No. 4 (75 mm) sieve.
<br />if less than 5 percent of the test sample passed the No. 200 ~(75
<br />µm) sieve, compote the coefficient of uniformity, Cu, and coeffi-
<br />cient of curvature, CZ, as given in Formulas 18-1-1 and 18-1-2:
<br />D~
<br />Dro
<br />2
<br />CZ = (D3o) (18-1-2)
<br />Dro x D~
<br />in which Dtp, D30 and D60 are the particle size diameters corre-
<br />sponding respectively to 10, 30 and 60 percent passing on the cu-
<br />mulative particle size distribution curve.
<br />Classify the sample aswell-graded gravel, GW, orwell=graded
<br />sand, SW, if ~ is greater than 4 for gravel and 6 for sand; and Cl is
<br />between 1 and 3. Classify the sample as poorly graded gravel, GP,'
<br />or poorly graded sand, SP, if either the Cu or the CZ criteria for
<br />well-graded soils are not satisfied.
<br />If more than 12 percent of the test sample passed the No. 200 (75
<br />µm) sieve, determine the liquid limit and the plasticity index of a
<br />portion of the test sample passing the No. 40 (425 µm) sieve in ac-
<br />cordance with approved methods.
<br />Classify the sample as silty gravel, GM, or silty sand, SM, if the
<br />results of the limits tests show that the fines are silty, that is, the
<br />plot of the liquid limit versus plasticity index falls below the "A"
<br />line (see Plasticity Table 18-1-A) or the plasticity index is less
<br />than 4.
<br />Classify the sample as clayey gravel, GC, or clayey sand, SC, if
<br />the fines are clayey, that is, the,plot of liquid limit versus plasticity
<br />index falls above the "A" line and the plasticity index is greater
<br />than 7.
<br />if the fines are intermediate between silt and clay, that is, the
<br />plot of liquid limit versus plasticity index falls on.or practically on
<br />the "A"line or falls above the "A" line but the plasticity index is in
<br />the range of 4 to 7, the soil should be given a borderline classifica-
<br />tion, such as GM-GC or SM-SC.
<br />If 5 to 12 percent of the test sample passed the No. 200 (75 µm)
<br />sieve, the soil should be given a borderline classification based on
<br />both its gradation and limit test characteristics, such as GW-GC or
<br />SP-SM. (In doubtful cases the rule is to faror the less plastic clas-
<br />
|