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1、1AS 1289.3.1.11995 Australian Standard Methods of testing soils for engineering purposes Method 3.1.1: Soil classification tests Determination of the liquid limit of a soil Four point Casagrande method 1SCOPEThis method covers the determination of the liquid limit of an air-dried or low-temperature
2、(50C) oven-dried soil, i.e. the moisture content at which a soil passes from the plastic to the liquid state. The method may also be used on a sample of soil in its natural state (see Note 1). 2REFERENCED DOCUMENTSThe following documents are referred to in this Standard: AS 1289Methods of testing so
3、ils for engineering purposes 1289.1Method 1:Preparation of disturbed soil samples for testing 1289.2.1.1 Method 2.1.1: Soil moisture content testsDetermination of the moisture content of a soilOven drying method (standard method) 1289.2.1.4 Method 2.1.4: Soil moisture content testsDetermination of t
4、he moisture content of a soilMicrowave-oven drying method (subsidiary method) 1289.2.1.5 Method 2.1.5: Soil moisture content testsDetermination of the moisture content of a soilInfrared lights method (subsidiary method) 1289.B3.1 Method B3.1:SoilmoisturecontenttestsEstablishmentofcorrelation between
5、 a subsidiary method of moisture content determination and the standard method AS 1289.2.1.1 BS 903Methods of testing vulcanized rubber Part A26:Determination of hardness 3APPARATUSThe following apparatus is required: (a)A thick, flat, rigid mixing plate of suitable size made of non-absorbent materi
6、al. (b)A mixing bowl of convenient size with a suitable close-fitting lid. (c)Palette knives of convenient size, e.g. having a blade 200 mm long and 30 mm wide. (d)Liquid limit apparatus conforming in the essential details to the device illustrated in Figure 1 (see Note 2). (e)A grooving tool and ga
7、uge similar in essential details to that illustrated in Figure 2 or Figure 3. (f)A wash bottle or beaker containing potable water (see Note 3). COPYRIGHT Accessed by TAFE QUEENSLAND INSTITUTES on 19 Dec 2007 AS 1289.3.1.119952 millimetres LetterABCDEFGHJ Dimension54 0.52 +0, 0.427 0.512.5 0.58 125 0
8、.510 0.516 0.560 1 millimetres LetterKLMNPQRST Dimension50 51501302728 0.5Ref R and S22 0.519 0.540 NOTES: 1 Essential dimensions are toleranced. 2 The cam may be manufactured from two semicircular sections with a common tangent point. degrees LetterVW Angle75 5100 3 FIGURE 1STANDARD LIQUID LIMIT AP
9、PARATUS COPYRIGHT Accessed by TAFE QUEENSLAND INSTITUTES on 19 Dec 2007 3AS 1289.3.1.11995 LetterABCDEF Dimension2 +0.5, 0.111 0.2540 0.258 0.2551 0.251.6 0.1 LetterGHJKLMN Dimension102050255010 0.2520 NOTES: 1Essential dimensions are toleranced. 2A suitable height gauge may be incorporated as part
10、of the grooving tool. FIGURE 2GROOVING TOOL AND HEIGHT GAUGE (Brass, stainless steel or plated steel) LetterABCDEFGH Dimension2 +0.5 0.113.5 0.2510 0.2522 0.256681690 LetterJKLMN Dimension85610 0.2510 0.25 NOTE: Essential dimensions are toleranced. FIGURE 3ALTERNATIVE GROOVING TOOL (Brass, stainless
11、 steel or plated steel) COPYRIGHT Accessed by TAFE QUEENSLAND INSTITUTES on 19 Dec 2007 AS 1289.3.1.119954 4ADJUSTMENT OF APPARATUSThe apparatus shall be adjusted as follows: (a)Inspect the liquid limit apparatus to determine that the device is clean and dry and in good working order, also that the
12、cup falls freely, and the total side-to-side play at the hinge when measured at the front-centre of the bowl does not exceed 3 mm. (b)Inspect the grooving tool to determine that it is clean and dry and that the width of the tip of the tool does not exceed 2.5 mm (see Note 4). (c)Adjust the height to
13、 which the cup of the liquid limit device is lifted so that when the cup is raised to its maximum height the 10 mm gauge will only just pass between it and the base. 5PROCEDUREThe procedure shall be as follows: (a)Obtain a sample of at least 250 g from the material passing the 425 m sieve which has
14、been prepared in accordance with AS 1289.1 (see Note 5). Then proceed as follows: (i)Record the method of preparation (see Note 1). (ii)Place the sample in the mixing bowl or on the mixing plate and thoroughly mix with the water using the palette knives and adding the water in increments. (iii)Thoro
15、ughly mix each increment of the water into the soil. (iv)Continueaddingwaterandmixinguntilthesoilbecomesathick homogeneous paste (see Note 6). (v)Cover the soil and allow to cure for at least 12 h at room temperature (see Note 7). (b)Thoroughly remix the cured soil on the mixing plate, or in the bow
16、l, for at least 1 min. (c)Place a portion of the soil-water mixture in the cup with the cup resting on the base and proceed as follows: (i)Level off the mixture parallel to the base to give a depth of soil in the cup of about, but not greater than, 10 mm. Hold the grooving tool normal to the surface
17、 of the cup, with the chamfered edge facing in the direction of movement and divide the soil by drawing the grooving tool along the diameter through the centre-line of the hinge. (ii)Check to see that the underside of the bowl and the top of the rubber block of the liquid limit device are free of so
18、il or water. (iii)Turn the crank at the rate of 2 r/s so that the cup is lifted and dropped until the two parts of the soil come into contact along the bottom of the groove for a distance of 10 mm. (iv)Record the number of blows at which this occurs. For the first point, if the number of blows is be
19、tween 35 and 40, proceed as below; if not, add water, or dry in air, as appropriate, and remix for about 3 min and repeat Step (c) until this condition is obtained. (d)Return the soil to the bowl or mixing plate and re-mix thoroughly for about 30 s. Clean and dry the cup of the machine and the groov
20、ing tool. (e)Repeat Steps (c) and (d) until the difference between the number of blows for closure in two consecutive tests is not greater than one (see Notes 8 and 9). COPYRIGHT Accessed by TAFE QUEENSLAND INSTITUTES on 19 Dec 2007 5AS 1289.3.1.11995 (f)Remove a quantity of soil (about 10 g) with a
21、 spatula from the portions of the sample that have just flowed together and determine its moisture content in accordance with AS 1289.2.1.1 (see Notes 10 and 11). (g)Carry out the operations in Steps (c) to (f) at least four times, using the same sample to which further increments of the water have
22、been added followed by thorough mixing for at least 1 min after each addition of water. Choose the moisture contents or the amount of water added so that, when the results are plotted, they are evenly distributed over a range of between 40 and 15 blows. Always proceed from the drier to the wetter co
23、ndition of the soils (see Note 9). If at any time during the course of the test procedure, the number of blows to give closure of the groove increases with the addition of water, all previous moisture content samples must be rejected and fresh attempts made to stabilize the blows versus moisture con
24、tent relationship commencing from Step (c). 6CALCULATIONSPlot moisture content and corresponding number of blows on a semi-logarithmic chart with the percentage moisture contents as ordinates on the linear scale and the number of blows as abscissae on the logarithmic scale. Draw a straight line best
25、 fitting the plotted points (flow curve). Determine the moisture content corresponding to the intersection of the flow curve with the point corresponding to 25 blows on the abscissa. This moisture content is the liquid limit wLof the soil. Alternatively, the equation to the line of best fit for loga
26、rithm of the number of blows versus moisture content can be calculated and thus the moisture content corresponding to 25 blows can be determined (see Note 12). 7TEST REPORTReport the percentage liquid limit wLto the nearest whole number. Also include in the report (a)the history of the sample, i.e.
27、natural state, air-dried, oven-dried or unknown; (b)the method of preparation, i.e. wet-sieved or dry-sieved; (c)reference to the test method used for determination of moisture content, if not standard; and (d)reference to this test method, i.e. AS 1289.3.1.1. NOTES ON TEST: 1Alternative preparation
28、 of sample (a)When no stones are present in the soil and practically all of it passes the 425 m sieve, it is often convenient to test samples without preparing them as described previously. When a soil is tested in the natural condition, the result will often differ from that obtained with an air-dr
29、ied or low-temperature (50C) oven-dried sample. (b)If stones are present, use only the material passing the 425 m sieve for the test. This can be achieved by rubbing the wet soil through the sieve until a sufficient quantity is obtained. The sieve used for this process should not be one of a set use
30、d for a particle size analysis, as the rubbing of wet soil through a sieve results in rapid wear of the sieve. This wear, however, will not have any appreciable effect on the liquid limit obtained for the sample under test. 2 Specification of the baseThe base of the liquid limit apparatus is made ei
31、ther of four equal-thickness laminations of vulcanized rubber bonded into a block of the dimensions given in Figure 1, or from a single vulcanized rubber block (natural rubber with carbon black loading) finished to the dimensions given in Figure 1. The hardness of the finished block, measured on the
32、 upper and lower surfaces of the complete block COPYRIGHT Accessed by TAFE QUEENSLAND INSTITUTES on 19 Dec 2007 AS 1289.3.1.119956 by Method N given in BS 903, Part A26:1969, at 20 2C shall be in the range 86 to 94 IRHD. The interval between checking of the hardness of the base and using the apparat
33、us should not exceed 2 years if the hardness lies in the range 91 to 94 IRHD or 3 years if the hardness lies in the range 86 to 90 IHRD. 3 WaterSome types of clay can be affected by poor or marginal potable water. In such cases, and when testing for reference purposes, distilled, demineralized or de
34、ionized water should be used. 4 Wear on the grooving tool and cupWhen the tip of the grooving tool has worn to a width of 2.5 mm, withdraw the tool from use and either re-shape it to the correct dimensions or replace it. It may be found useful to have a standard gauge of the correct dimensions again
35、st which the tool can be checked. The cup is subject to wear by the grooving tool and should be replaced when the depth of wear exceeds 0.2 mm. 5 If the plasticity index is to be calculated using the results from this test, the same method of preparation should be used for both the liquid limit and
36、the plastic limit test. 6 Consistency of soilWith cohesive soils the consistency of the mixture should be such that, when placed in the liquid limit apparatus, about 35 to 40 blows are required for closure. 7 Curing of soil prior to testingAfter final mixing and before performing the test, cohesive
37、soils should stand for at least 12 h in a covered container to allow the water to permeate throughout the soil mass. Some clayey soils may require to stand for 24 h to allow thorough permeation of the water through the soil. If tested without curing, inconclusive results may occur, particularly with
38、 some types of soft clayey soils. After curing, the soil should be thoroughly remixed for at least 1 min before testing. 8 Slippage in the cupSome soils tend to slide on the surface of the cup instead of flowing so that the groove closes at a false, low number of blows. If this occurs, the results s
39、hould be discarded and the test repeated. If sliding still occurs, increments of water should be added until sliding ceases. If sliding always occurs, the test is not applicable and a note should be made that the liquid limit could not be obtained. 9 Prevention of drying of test materialTake care th
40、at the sample does not dry out between tests as the number of blows for closure will increase gradually as the sample dries out. If the soil has to be left for a time, cover it with an evaporating dish or damp cloth to prevent it from drying out. 10 Size of moisture content sampleThe quantity of abo
41、ut 10 g which is taken as the moisture content sample is less than that recommended in AS 1289.2.1.1. However, because of the homogeneity of the soil which constitutes the sample it is considered to be a satisfactory quantity. 11 Moisture content determinationMoisture content may be determined using
42、 other methods such as AS 1289.2.1.4 or AS 1289.2.1.5 provided a suitable correlation of the method for the soil has been determined in accordance with AS 1289.B3.1. 12 Line of best fitEither of these procedures is suitable provided that at least three points are included which show a decreasing moi
43、sture content as the number of blows increases. Any point which does not show this trend shall be excluded and the number of points used shall be reported. In cases where there are not three such points, the test shall be repeated on a separate portion of the sample. COPYRIGHT Accessed by TAFE QUEEN
44、SLAND INSTITUTES on 19 Dec 2007 7AS 1289.3.1.11995 NOTES Accessed by TAFE QUEENSLAND INSTITUTES on 19 Dec 2007 AS 1289.3.1.119958 This Australian Standard was prepared by Committee CE/9, Testing of Soils for Engineering Purposes. It was approved on behalf of the Council of Standards Australia on 1 N
45、ovember 1994 and published on 5 March 1995. Review of Australian Standards.To keep abreast of progress in industry, Australian Standards are subject to periodic review and are kept up to date by the issue of amendments or new editions as necessary. It is important therefore that Standards users ensu
46、re that they are in possession of the latest edition, and any amendments thereto. Full details of all Australian Standards and related publications will be found in the Standards Australia Catalogue of Publications; this information is supplemented each month by the magazine The Australian Standard,
47、 which subscribing members receive, and which gives details of new publications, new editions and amendments, and of withdrawn Standards. Suggestions for improvements to Australian Standards, addressed to the head office of Standards Australia, are welcomed. Notification of any inaccuracy or ambigui
48、ty found in an Australian Standard should be made without delay in order that the matter may be investigated and appropriate action taken. First published as AS A89.2A1966. Revised and redesignated as AS 1289.C1.11977. Revised and redesignated as AS 1289.3.1.11995. Incorporating: Amdt 11998 This Sta
49、ndard was issued in draft form for comment as DR 93337. CopyrightSTANDARDS AUSTRALIA Users of Standards are reminded that copyright subsists in all Standards Australia publications and software. Except where the Copyright Act allows and except where provided for below no publications or software produced by Standards Australia may be reproduced, stored in a retrieval system in any form or transmitted by any means without prior permission in writing from Standards Australia. Permission may be conditional on an appropriate royalty paym
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