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1、 1 AS 1289.5.7.12006 Standards Australia Australian Standard TM Methods of testing soils for engineering purposes Method 5.7.1: Soil compaction and density testsCompaction control testHilf density ratio and Hilf moisture variation (rapid method) 1 SCOPE This Standard sets out a rapid method for dete
2、rmining compaction control parameters for soils. The method involves relating converted wet density (CWD) of the laboratory- compacted soil to added moisture (Z) without the need to determine moisture content. The test is based on standard compactive effort in accordance with AS 1289.5.1.1. If modif
3、ied compactive effort in accordance with AS 1289.5.2.1 is used, experimental data must initially be accumulated for that particular soil in order for the moisture variation to be reliably assessed (see Note to Clause 4.2(h). Because this is a rapid method, there may be minor differences between resu
4、lts obtained by this procedure and results obtained by the method of compaction control given in AS 1289.5.4.1. This procedure is applicable to the portion of soil that passes a 37.5 mm sieve. Corrections can be made to values determined by this method for soil with up to 20% oversize material. Soil
5、 that passes a 19.0 mm sieve is compacted in a 105 mm diameter mould. Soil that contains more than 20% of material retained on a 19.0 mm sieve is compacted in a 152 mm diameter mould. Because of the omission of proper curing, this method might not be reliable for soils that are much wetter or drier
6、than the optimum moisture content. Further, because of the empirical basis for the calculation of moisture variation, the method is limited to added moisture values (Z) between 4% and +6% (see Figure 1). This method may be used for checking material before placement to ensure that the moisture conte
7、nt is within specified limits (see Note to Clause 4.2(h). 2 REFERENCED DOCUMENTS The following documents are referred to in this Standard: AS 1152 Specification for test sieves 1289 Methods of testing soils for engineering purposes 1289.1.1 Method 1.1: Sampling and preparation of soilsPreparation of
8、 disturbed soil samples for testing 1289.5.1.1 Method 5.1.1: Soil compaction and density testsDetermination of the dry density/moisture content relation of a soil using standard compactive effort AS 1289.5.7.12006 Accessed by TAFE QUEENSLAND INSTITUTES on 04 Dec 2007 AS 1289.5.7.12006 2 Standards Au
9、stralia .au AS 1289.5.2.1 Method 5.2.1: Soil compaction and density testsDetermination of the dry density/moisture content relation of a soil using modified compactive effort 1289.5.3.1 Method 5.3.1: Soil compaction and density testsDetermination of the field density of a soilSand replacement method
10、 using a sand-cone pouring apparatus 1289.5.3.2 Method 5.3.2: Soil compaction and density testsDetermination of the field dry density of a soilSand replacement method using a sand pouring can, with or without a volume displacer 1289.5.3.5 Method 5.3.5: Soil compaction and density testsDetermination
11、of the field dry density of a soilWater replacement method 1289.5.4.1 Method 5.4.1: Soil compaction and density testsCompaction control test Dry density ratio, moisture variation and moisture ratio 1289.5.8.1 Method 5.8.1: Soil compaction and density testsDetermination of field density and field moi
12、sture content of a soil using a nuclear surface moisture-density gaugeDirect transmission mode 3 APPARATUS The following apparatus is required: (a) A cylindrical metal mould appropriate to the size of material as described in AS 1289.5.1.1 or AS 1289.5.2.1. (b) A steel rammer, or an alternative mech
13、anical compaction device, as described in AS 1289.5.1.1 or AS 1289.5.2.1. (c) A level rigid foundation on which to compact the specimen, e.g., a sound concrete floor approximately 100 mm or more in thickness, or a concrete block of at least 100 kg mass. (d) A balance of suitable capacity with a limi
14、t of performance not greater than 5 g. (e) Sieves, 37.5 mm and 19.0 mm, complying with AS 1152. (f) A strong spatula or a suitable knife. (g) A steel straightedge, approximately 250 mm long, 25 mm wide and 3 mm thick, and preferably with one bevelled edge. (h) Miscellaneous mixing apparatus, such as
15、 pan or bowl, spoon, trowels and water spray, suitable for thoroughly mixing increments of water with the soil. (i) A rule graduated in millimetres or a layer depth gauge. (j) Sealable containers suitable for curing moistened soil samples. (k) A siphon can and a calibrated volumetric measuring cylin
16、der. (l) A sample extractor, such as a jack, lever, frame or other device, suitable for extruding compacted soil specimens from the mould (optional). (m) A soil grater for fine-grained materials (optional). Accessed by TAFE QUEENSLAND INSTITUTES on 04 Dec 2007 3 AS 1289.5.7.12006 .au Standards Austr
17、alia 4 PROCEDURE 4.1 Sampling and preparation The validity of the method depends upon the field-in-place moisture content and the moisture content of the split compaction samples (prior to wetting or drying) being substantially the same; therefore, considerable care should be taken to ensure that mo
18、isture loss is minimized during the sampling, preparation and compaction procedures. The procedure shall be as follows: (a) Determine the field wet density of the soil () using the method described in AS 1289.5.3.1, AS 1289.5.3.2, AS 1289.5.3.5 or AS 1289.5.8.1. (b) Obtain a bulk sample of the soil
19、for the compaction test from the material excavated during the in situ density test. If this material is insufficient for the bulk sample, obtain additional material immediately after completion of the field density test by enlarging the density hole laterally to a depth approximately equal to but n
20、ot exceeding the depth of the field density test hole. The sides of any excavation made to recover the required bulk sample of material shall be reasonably vertical. For sites for which the field density has been determined by a nuclear surface moisture-density gauge, obtain the bulk sample by excav
21、ating a hole centred between the nuclear source and the detector in the gauge. The depth of the excavation shall be equal to the depth of insertion of the source rod during the field density test. The sides of any excavation made to recover the required bulk sample of material shall be reasonably ve
22、rtical. Collect, transport and store samples in sealable containers. (c) Prepare the sample in accordance with AS 1289.1.1. (d) Determine the total mass (m) of the wet material. Screen the prepared sample over a 19.0 mm sieve. Determine the wet mass (mo) of the material retained on the 19.0 mm sieve
23、. Calculate the percentage of oversize material using the equation m m P o o 100 =. . . 4.1 where Po = the percentage of material by mass retained on sieve, based on the wet mass of the total material and the oversize material mo = the wet mass of oversize material, in grams m= the wet mass of the t
24、otal sample before screening, in grams If more than 20% of the material is retained on the 19.0 mm sieve, screen this material over a 37.5 mm sieve. When material is retained on this sieve, determine its wet mass and calculate the percentage of oversize material on the wet mass basis, as above. (e)
25、If oversize material is present, determine the volume (Vo) of the oversize material by methods such as measuring its displacement of water using a siphon can or a calibrated volumetric measuring cylinder. (f) Select the size fraction and mould size to be used in the compaction test using the criteri
26、a in Table 1. Record the mould used as type A or B. When necessary, recombine the material passing the 37.5 mm sieve and that passing the 19.0 mm sieve and thoroughly mix. Accessed by TAFE QUEENSLAND INSTITUTES on 04 Dec 2007 AS 1289.5.7.12006 4 Standards Australia .au (g) Split out three or more re
27、presentative portions of the screened soil, each of sufficient quantity to produce a compacted volume in excess of the volume of the mould. NOTE: For material compacted in a 105 mm diameter mould, a mass of 2.5 kg will be adequate for most soils. Gravel may require up to 3 kg, while it may be possib
28、le to use as little as 2 kg of heavy clay. For material compacted in a 152 mm diameter mould, about 2.5 times the material required for a 105 mm diameter mould will be required. Sample sufficient soil in case three points are not adequate. Generally, 15 kg of soil when using a 105 mm diameter mould,
29、 and 40 kg of soil when using a 150 mm diameter mould, should be adequate. (h) If required, determine the field moisture content (wf) of a representative portion of the sample. TABLE 1 SIZE FRACTION AND MOULD TYPE Percent retained 37.5 mm sieve 19.0 mm sieve Test mould typePortion to be tested 20 No
30、t testable using this method 20 20 B All material passing 37.5 mm sieve 20 A All material passing 19.0 mm sieve 4.2 Compaction The samples shall be compacted in the following manner: (a) Take a portion of the screened soil as prepared in Clause 4.1(g). Add or remove moisture, or leave as is, so that
31、 the soil is at the optimum moisture content. Record the amount of moisture added or removed. NOTES: 1 Increments of 2% are usually suitable for cohesive soils; however, in some cases more compaction points or different moisture increments may be needed. In particular, for non- cohesive soils the mo
32、isture increments may need to be 0.5% to 1.0%. 2 Dry out soil samples that are wetter than the optimum moisture content. To accelerate the drying process, a special sample drier may be used. This usually consists of a 450 mm diameter 425 m sieve supported by a coarser mesh mounted over a fan-heater
33、with a small metal cone between them. Alternatively, infra-red lights or a fan that blows air across the soil may be used. The soil should be turned from time to time to assist evaporation. 3 It is important that moisture not be lost from the sample portions during preparation and testing. (b) Thoro
34、ughly mix the portion to ensure uniform distribution of moisture through the soil. Compact the portion of soil as described in AS 1289.5.1.1 or AS 1289.5.2.1 and calculate the wet density of the compacted specimen. (c) Calculate the corresponding converted wet density for the specimen using the equa
35、tion ()1001 w ZCWD+= . . . 4.2(1) where CWD= converted wet density, in tonnes per cubic metre w = wet density of the compacted specimen, in tonnes per cubic metre Z= the added moisture based on the original mass of wet soil, in percent Accessed by TAFE QUEENSLAND INSTITUTES on 04 Dec 2007 5 AS 1289.
36、5.7.12006 .au Standards Australia (d) Prepare another portion of soil so that the soil is either wetter or drier than the optimum moisture content. Compact the soil in Step (b) and calculate CDW as in Step (c). Record the amount of moisture added or removed (see Notes 1 and 2 to Clause 4.2(a). (e) R
37、epeat Step (d) using an essentially equal increment of water to achieve another point on the other side of the optimum moisture content to that obtained in Step (d). (f) Plot the converted wet density as ordinate versus the moisture increment as abscissa. If a point that is higher in ordinate value
38、than points to the left and right, or equal to one of them, is not obtained, repeat Step (e). (g) Draw a smooth curve approximating a parabola through the points (an analytical or computer-derived curve may also be used) and then determine the coordinates of the peak point of the converted wet densi
39、ty (CWD) versus added moisture (Z) curve (PCWD and Zm). (h) When required, use the correction curves in Figure 1 to find the moisture content correction (wc) for the peak point to the nearest 0.1%. This moisture correction can also be determined analytically. NOTE: The moisture correction curves sho
40、wn in Figure 1 yield a close approximation to the value of moisture variation for a wide range of soils subjected to standard compaction. The curves are based on experimental data collected by Hilf,* which gives the following relation between maximum wet density (wmax.) and optimum moisture content
41、(wo): o max. 080. 8 527. 1 w w+= . . . 4.2(2) where wmax.= maximum wet density, in tonnes per cubic metre wo = optimum moisture content, in percent Using this empirical relationship, the moisture correction is given by the following equation: + + = 100 527 . 1 100 1 0808. 0 100 100 m mm m c Z Z PCWD
42、 Z Z w . . . 4.2(3) and moisture variation (wv) is given directly by + + + = 527. 1 100 1 0808 . 0 1 100 100 mm m v Z PCWD Z Z w . . . 4.2(4) where wc = moisture correction, in percent Zm = added moisture corresponding to the peak point, in percent PCWD= peak converted wet density of material, in to
43、nnes per cubic metre wv = moisture variation, in percent * HILF, J.W. A rapid method of construction control for embankments of cohesive soil. U.S. Department of the Interior, Water Resources Technical Publications, Engineering Monograph No. 26, 1966. U.S. BUREAU OF RECLAMATION, Earth manual: U.S. D
44、epartment of the Interior, Designation E.25. AMERICAN SOCIETY FOR TESTING AND MATERIALS, Special procedures for testing soil and rock for engineering purposes. 5th ed. STP 479: 1970. Accessed by TAFE QUEENSLAND INSTITUTES on 04 Dec 2007 AS 1289.5.7.12006 6 Standards Australia .au These equations app
45、ly for the range of Zm and PCWD values shown in Figure 1. The above empirical relationship may not be applicable to modified compaction for soils with very high or very low values of laboratory maximum dry density or for unusual soils. This will be indicated by wv (as calculated using the correction
46、 curves in Figure 1 or the equivalent formula as detailed above) being consistently different from the true value of wv deduced after the field moisture content has been determined. In such cases deduce a new empirical relationship between laboratory maximum wet density and optimum moisture content
47、and thus new moisture correction curves or a new moisture correction equation. NOTE: Optimum moisture content control of moisture content within specified limits is often done with reference to the modified or standard optimum moisture content. The optimum moisture content (wo) can be obtained from
48、the following equation: m f fo 100 1Z w ww +=. . . 4.2(5) where wo = optimum moisture content, in percent wf = field moisture content, in percent Zm = added moisture corresponding to the peak point, in percent 5 CALCULATIONS Calculate as follows: (a) The moisture variation (wv) to the nearest 0.1% u
49、sing the following equation (see Note to Clause 4.1(g): wv = Zm + wc . . . 5(1) where wv = moisture variation, in percent Zm = added moisture corresponding to the peak point, in percent wc = moisture correction, in percent (b) When oversize material is present, the peak converted wet density (PCWD) is adjusted for the oversize material using the following eq