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.. . .... . ..... __.__..._ . __ EXHIBIT D UNIFORM BUILDING CODE STANDARD 18-1 SOILS CLASSIFICATION Based on Standard Method D 2487-69 of the American Society for Testing and Materials. Extracted, with permission, from the Annual Book of ASTM Standards, copyright American Society for Testing and Materials, 100 Barr Harbor Drive, West Conshohocken, PA 19428 See Sections 18012 and 1803.1, Uniform Building Code SECTION 18.101 — SCOPE This standard describes a system for classifying mineral and or- ganomineral soils for engineering purposes based on laboratory determination of particle -size characteristics, liquid limit and plasticity index. SECTION 18.102 —APPARATUS Apparatus of an approved type shall be used to perform the fol- lowing tests and procedures: Preparation of soil samples, liquid limit test, plastic limit test and particle -size analysis. SECTION 18.108—SAMPLING Sampling shall be conducted in accordance with approved meth- ods for soil investigation and sampling by auger borings, for Pene- tration Test and Split -barrel Sampling of Soils, and for Thin-walled Tlrbe Sampling of Soils. The sample shall be carefully identified as to origin by a boring number and sample number in conjunction with a job number, a geologic stratum, a pedologic horizon or a location description with respect to a permanent monument, a grid system or a station number and offset with respect to a stated center line. The sample should also be described in accordance with an ap- proved visual -manual procedure. (A soil which is composed pri- marily of undecayed or partially decayed organic matter and has a fibrous texture, dark brown to black color, and organic odor should be designated as a highly organic soil, PT, and not sub- jected to the classification procedures described hereafter.) SECTION 18.104 —TEST SAMPLE Test samples shall represent that portion of the field sample finer than the 3 -inch (76 mm) sieve and shall be obtained as follows: Air dry the field sample; weigh the field sample; and separate the field sample into two fractions on a 3 -inch (76 mm) sieve. Weigh the fraction retained on the 3 -inch (76 mm) sieve. Compute the percentage of plus 3 -inch (76 mm) material in the field sample and note this percentage as auxiliary information. Thoroughly mix" the fraction passing the 3 -inch (76 mm) sieve and select test samples. SECTION 18.105 — PRELIMINARY CLASSIFICATION PROCEDURE Procedure for the determination of percentage Finer than the No. 200 (75 µm) sieve is as follows: 1. From the material passing the 3 -inch (76 mm) sieve, select a test sample and determine the percentage of the test sample finer than the No. 200 (75 µm) sieve. (Phis step may be omitted if the soil can obviously be classified as fine-grained by visual inspec- tion.) 2. Classify the soil as coarse-grained if more than 50 percent of the test sample is retained on the No. 200 (75 µm) sieve. 3. Classify the soil as fine-grained if 50 percent or more of the test sample passes the No. 200 (75 µm) sieve. SECTION 18.106 — PROCEDURE FOR CLASSIFICATION OF COARSE-GRAINED SOILS (MORE THAN 50 PERCENT RETAINED) Select test samples from the material passing the 3 -inch (76 mm) sieve for the determination of particle -size characteristics, liquid limit and plasticity index. Determine the cumulative particle -size distribution of the fraction coarser than the No. 200 (75 µm) sieve. Classify the sample as gravel; G, if 50 percent or more of the coarse fraction [plus No. 200 (75 µm) sieve) is retained on the No. 4 (4.75 mm) sieve. Classify the sample as sand, S, if more than 50 percent of the coarse fraction [plus No. 200 (75 µm) sieve] passes the No. 4 (75 mm) sieve. If less than 5 percent of the test sample passed the No. 200 (75 µm) sieve, compute the coefficient of uniformity, C,,, and coeffi- cient of curvature, q, as given in Formulas 18-1-1 and 18-1-2: C„= D� : (18-1-1) D.1 Cz = (D)2 (18-1-2) Dio x D60 in which Dlo, D30 and D60 are the particle size diameters corre- sponding respectively to 10, 30 and 60 percent passing on the cu- mulative particle size distribution curve. Classify the sample as well -graded gravel, GW, or well -graded sand, SW, if C„ is greater than 4 for gravel and 6 for sand, and Cz is between 1 and 3. Classify the sample as poorly graded gravel, GP, or poorly graded sand, SP, if either the C„ or the C, criteria for well -graded soils are not satisfied. If more than 12 percent of the test sample passed the No. 200 (75 µm) sieve, determine the liquid limit and the plasticity index of a portion of the test sample passing the No. 40 (425 gm) sieve in ac- cordance with approved methods. Classify the sample as silty gravel, GM, or silty sand, SM, if the results of the limits tests show that the fines are silty, that is, the plot of the liquid limit versus plasticity index falls below the "A" line (see Plasticity Table 18-1-A) or the plasticity index is less than 4. Classify the sample as clayey gravel, GC, or clayey sand, SC, if the fines are clayey,. that is, the plot of liquid limit versus plasticity index falls above the "A" line and the plasticity index is greater than 7. If the fines are intermediate between silt and clay, that is, the plot of liquid limit versus plasticity index falls on or practically on the "A" line or falls above the "A" line but the plasticity index is in the range of 4 to 7,' the soil should be given a borderline classifica- tion, such as GM -GC or SM -SC. If 5 to 12 percent of the test sample passed the No. 200 (75 µm) sieve, the soil should be given a borderline classification based on both its gradation and limit test characteristics, such as GW -GC or SP -SM. (In doubtful cases the rule is to favor the less plastic clas- 3-327