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1、1AS 1289.6.8.11995 Australian Standard Methods of testing soils for engineering purposes Method 6.8.1: Soil strength and consolidation testsDetermination of the resilient modulus and permanent deformation of granular unbound pavement materials 1SCOPEThis Standard covers the determination of both the
2、 resilient modulus and permanent deformation of unbound pavement materials with a maximum particle size not exceeding 19 mm using repeated load triaxial equipment with static confining pressure and an externalverticaldisplacementmeasuring deviceunderundrainedconditions without pore pressure measurem
3、ent. The same apparatus and similar test procedures are utilized to determine both of these properties. The resilient modulus test characterizes the material response over a range of applied dynamic stress conditions assuming isotropic behaviour. The permanent deformation test characterizes the plas
4、tic strain response at one stress level over a large number of repetitions. 2REFERENCED DOCUMENTSThe following documents are referred to in this Standard: AS 1141Methods for sampling and testing aggregates 1141.3Sampling of aggregates and rock 1152Specification for test sieves 1289Methods of testing
5、 soils for engineering purposes 1289.1Method 1:Preparation of disturbed soil samples for testing 1289.2.1.1Method 2.1.1: Soil moisture content testsDetermination of the moisture content of a soil Oven drying method (standard method) 1289.5.1.1Method 5.1.1: Soil compaction and density testsDeterminat
6、ion of the dry density/moisturecontentrelation of a soil using standard compactive effort 1289.5.2.1Method 5.2.1: Soil compaction and density testsDetermination of the dry density/moisturecontent relation of a soil using modified compactive effort 1289.E5.1Method E5.1:SoilcompactionanddensitytestsDe
7、terminationof minimumandmaximumdrydensityofacohesionless material 1289.F4.1Method F4.1:Soil strength and consolidation testsDetermination of the compressive strength of a soilCompressive strength of a specimen tested in undrained triaxial compression without measurement of pore pressure 1349Bourdon
8、tube pressure and vacuum gauges 1545Methods for the calibration and grading of extensometers COPYRIGHT Accessed by TAFE QUEENSLAND INSTITUTES on 19 Dec 2007 AS 1289.6.8.1 19952 AS 2193Methods for calibration and grading of force-measuring systems of testing machines 3DEFINITIONSFor the purpose of th
9、is Standard, the definitions below apply. 3.1Laboratory moisture ratiothe ratio of the moisture content of the specimen to the optimummoisture contentof the material, as determinedby AS 1289.5.1.1or AS 1289.5.2.1, expressed as a percentage. 3.2Laboratory density ratiothe ratio of the dry density of
10、the specimen to the maximum dry density of the material, as determined by AS 1289.5.1.1, AS 1289.5.2.1, or AS 1289 E5.1, expressed as a percentage. 4APPARATUSThe following apparatus shall be used: (a)Dynamic loading equipment capable of applying a vertical dynamic force of up to 5 kN and a static co
11、nfining pressure of up to 500 kPa (see Note 1). A general arrangement is shown in Figure 1 (see Note 2). The equipment shall meet the following requirements: (i)The vertical dynamic force loading cycle shall have a period of 3 s with rise and fall times of up to 0.3 s and load pulse width of 1 s (se
12、e Figure 2). (ii)The device for vertical load measurement shall meet the requirements of AS 2193 for Grade A testing machines. (iii)The loading equipment shall be capable of providing at least 106vertical load cycles continuously. (iv)The static confining pressure shall be controllablewithin 5 kPa o
13、f the required applied pressure and shall be measured at the base of the triaxial cell using a device which meets the accuracy requirements of AS 1349 for industrial gauges. (b)Standard triaxial cell for 100 mm diameter samples, with a working pressure of at least 500 kPa. (c)Vertical strain measuri
14、ng device with a range of 20 mm meeting the accuracy and repeatability requirements for a Grade B extensometer as defined in AS 1545. (d)Vernier callipers for measuring the length and diameter of the specimen to an accuracy of 0.2%. (e)Computer and data acquisition equipment capable of recording the
15、 data from the load and strain measuring devices to the required accuracy. (f)Compaction apparatus meeting the requirements of AS 1289.5.1.1 or AS 1289.5.2.1, as applicable. (g)A cylindrical metal mould capable of producing a specimen 100 1 mm diameter and 200 0.5 mm high with a collar of sufficient
16、 height to permit the filling of the mould in layers with loose soil prior to compaction. A split mould is preferred. (h)Hydraulic jack for extruding specimens from the mould (optional) (see Clause 7(c). (i)Seamless rubber membrane in the form of a tube, open at both ends, of internal diameter equal
17、 to that of the specimen and length about 50 mm greater than that of the specimen and of 0.25 mm to 0.60 mm thickness. (j)Membrane stretcher to suit the size of specimen. (k)Rubber rings of circular cross-section to suit the diameter of the end caps (see also AS 1289.F4.1). COPYRIGHT Accessed by TAF
18、E QUEENSLAND INSTITUTES on 19 Dec 2007 3AS 1289.6.8.1 1995 (l)A balance of at least 10 kg capacity with a limit of performance not exceeding 0.5 g. (m)Sealable containers suitable for curing moist samples. FIGURE 1SCHEMATIC OF TYPICAL REPEAT LOAD TRIAXIAL TEST APPARATUS COPYRIGHT Accessed by TAFE QU
19、EENSLAND INSTITUTES on 19 Dec 2007 AS 1289.6.8.1 19954 5TEST CONDITIONSThe following test conditions shall be specified: (a)The laboratory moisture ratio of the specimen during the test. (b)The laboratory density ratio of the specimen during the test. (c)The contact stress used for design purposes o
20、r confining and vertical stresses to be applied to the specimen for preconditioning, resilient modulus (see Table 1) and permanent deformation testing (see Table 2). (d)The compactive effort, standard or modified, to compact the specimen (see Notes 3 and 4). 6SAMPLEThe sample shall be obtained and p
21、repared as follows: (a)Obtain a bulk sample of the material to be tested in accordance with AS 1141.3. (b)Prepare the sample in accordance with the appropriate Section of AS 1289.1. Sieve the sample over the 19 mm sieve and discard the material retained on the 19 mm sieve (see Note 5). (c)Obtain by
22、riffling or splitting the sample prepared in Step (b) a representative sub- sample of about 5 kg for compaction and, if required, another of at least 300 g for moisture content determination. Place the subsamples in separate sealable containers. (d)If required, determine the moisture content of the
23、moisture content subsample obtained in Step (c) above in acordance with AS 1289.2.1.1. (e)Bring the subsample to the laboratory moisture ratio condition at which compaction is to be performed. Thoroughly mix the subsample and place it in a sealable container. (f)Allow the subsample to cure for an ap
24、propriate time for the soil type (see Note 6). (g)Split sufficient material from the cured subsample to fill the compaction mould and, if required, at least another 300 g for moisture content determination. (h)If required, determine the moisture content (w1) of the moisture subsample prepared in Ste
25、p (g). 7PREPARATION OF TEST SPECIMENSSeparate specimens shall be prepared for resilient modulus and permanent deformation tests, as follows: (a)Using the compaction subsample obtainedin Step 6(g), compact the soil into the mould to the required density. Unless otherwise specified, the material is to
26、 be compacted in 6 layers when using a hammer as described in AS 1289.5.1.1 or 10 layers when using a hammer as described in AS 1289.5.2.1 (see Notes 3 and 4). Proceed as follows: (i)Clean the mould and place the collar on its top. (ii)Determine themass (m1) of themouldand collar(with baseplate,if a
27、ppropriate). (iii)Assemble the mould, collar and baseplate and place the assembly on a rigid foundation. (iv)Compact the specimen to the required density level in the required number of layers. Compact each layer by uniformly distributed blows of the rammer falling freely from the specified height (
28、300 mm for standard compactive effort or 450 mm for modified compactive effort). Use only sufficient soil in each layer so that the compacted layer thickness of each layer does not vary by more than 5 mm from any other layer. It is recommended that the top COPYRIGHT Accessed by TAFE QUEENSLAND INSTI
29、TUTES on 19 Dec 2007 5AS 1289.6.8.1 1995 5 mm of each layer be scarified prior to placing the material for the next layer in the mould. Use only sufficient soil to slightly overfill the mould leaving not more than 5 mm to be struck off after removing the collar. The number of blows will depend on th
30、e density level required and the number of layers (see Notes 3 and 4). (v)Level the material to the top of the mould by means of the straight-edge; smooth the top of the specimen by adding a small amount of fines obtained from the material to fill surface irregularities. The fines shall pass a 1.18
31、mm aperture size sieve complying with AS 1152. (b)Determine the mass (m2) of the mould, collar and wet specimen, with baseplate if appropriate. (c)Remove the specimen from the mould by either disassembling the split mould or extruding the specimen from the mould using a hydraulic jack. Ensure that t
32、he specimen is not damaged during the demoulding process (see Note 7). (d)Measure the length (hs) and diameter (ds) of the specimen to the nearest 0.5 mm. 8PROCEDURE 8.1Specimen assemblyProceed as follows: (a)Place the triaxial cell base on the platform of the loading machine. (b)To ensure that the
33、test is performed undrained, isolate the pore pressure port in the base pedestal by using a polycarbonate disc between the specimen and the pedestal. (c)Place the specimen centrally on the base pedestal and place the loading cap on top of the specimen. Using the membrane stretcher, place the rubber
34、membrane around the specimen and seal the membrane at both end platens by means of the rubber rings. (d)Assemble the triaxial cell into position ensuring that the loading ram is seated centrally in the load cap. (e)Attach the displacement measuring device to the loading ram so that it is set up to o
35、perate within its calibrated range. (f)Fill the cell with the liquid to be used for applying the confining pressure and remove air bubbles. 8.2Preconditioning for the resilient modulus testPreconditioning is to be performed for the resilient modulus test to allow the end caps to bed into the specime
36、n and to allow the resilient strain to stabilize under the imposed stress conditions. The preconditioning stresses to be used for testing will depend on the stresses to be applied during the resilient modulus test. The required values may be obtained from Table 1 by selecting (a)for base materials (
37、0 to 100 mm in the pavement). . . . . . . . . . . . . . . . .level 1; (b)for upper sub-base materials (100 to 200 mm in the pavement). . . .level 13; and (c)for lower sub-base materials (200 mm in the pavement). . . . . . . . . . . . level 22. Other stress levels may be specified if required. A cont
38、act stress (p) in the range 550 to 700 kPa is normally selected. If the test is to characterize multiple pavement layers, preconditioning is to be carried out for the lowest pavement layer followed by resilient modulus determination (see Clause 8.3), and repeated for higher pavement layers. Proceed
39、as follows: (i)Apply and hold the selected confining pressure. COPYRIGHT Accessed by TAFE QUEENSLAND INSTITUTES on 19 Dec 2007 AS 1289.6.8.1 19956 (ii)Apply loading/unloading cycles (see Figures 2 and 3) of the specified vertical stress to the specimen for at least 50 loading cycles and calculate th
40、e resilient modulus of the specimen after each cycle greater than 50. Continue the application of the loading/unloading cycles until the resilient modulus values determined from the last six results vary by less than 5 % of the mean value of those six results or until 1000 cycles have been completed
41、, whichever occurs first (see Note 8). TABLE1 STRESS LEVELS FOR PRECONDITIONING AND RESILIENT MODULUS Stress level numberPavement layer1/p3/1 1 2 3 4 5 6 7 8 9 10 11 Base 0 to 100 mm in the pavement 0.43 0.64 0.85 0.67 0.94 0.77 1.00 1.00 0.45 0.70 0.30 0.167 0.167 0.167 0.300 0.300 0.400 0.400 0.67
42、0 0.100 0.100 0.050 12 13 14 15 16 17 18 19 20 Upper sub-base 100 to 200 mm in the pavement 0.40 0.20 0.60 0.50 0.30 0.20 0.20 0.30 0.40 0.100 0.100 0.100 0.070 0.070 0.070 0.050 0.050 0.050 21 22 23 24 25 26 27 28 29 Lower sub-base 200 mm in the pavement 0.20 0.10 0.40 0.30 0.20 0.10 0.10 0.20 0.30
43、 0.100 0.100 0.100 0.070 0.070 0.070 0.050 0.050 0.050 LEGEND: 1=axial stress 3=confining stress p=contact stress at the surface of the pavement 8.3Determination of resilient modulusProceed as follows: (a) For the pavement layer to be tested, determinevertical stresses and confining pressures to be
44、used from Table 1, or as otherwise specified. COPYRIGHT Accessed by TAFE QUEENSLAND INSTITUTES on 19 Dec 2007 7AS 1289.6.8.1 1995 FIGURE 2ILLUSTRATION OF THE VERTICAL FORCE WAVEFORM FIGURE 3ILLUSTRATION OF TERMS (b) In sequential order, for each stress level selected in Item (a), apply and hold the
45、confining pressure to the specimen, then apply the cycles of loading and unloading of the specified vertical stress for at least 50 cycles and calculate the resilient modulus of the specimen after each cycle greater than 50. Continue the application of the loading/unloading cycles until the resilien
46、t modulus values determined from the last six results vary by less than 5 percent of the mean value of those six results or until 200 cycles at each stress level have been completed. (c) Remove the specimen from the cell and determine the moisture content (w) of the whole specimen in accordance with
47、 AS 1289.2.1.1. 8.4Determination of permanent deformationThis test is performed on a separate specimen to that used for determination of resilient modulus. A separate specimen shall be used for each stress level number selected. The test procedure includes preconditioning to allow for settlement of
48、the specimen into the equipment and therefore no separate preconditioning is applied. Proceed as follows: (a) Select the stress level to be used from Table 2 or as otherwise specified, and the corresponding confining pressure and vertical stress to be applied from Table 1. COPYRIGHT Accessed by TAFE
49、 QUEENSLAND INSTITUTES on 19 Dec 2007 AS 1289.6.8.1 19958 TABLE2 STRESS LEVELS FOR PERMANENT DEFORMATION TEST Pavement levelStress level Base Upper sub-base Lower sub-base 5 15 23 (b)Apply and hold the selected confining pressure to the specimen and then apply the cycle of loading and unloading of the specified vertical stress (see Figure 2) for at least 5 104cycles. At least 10 reading sets of permanent deformation and applied stress measurements and resilient modulus shall be taken. (c)Remove the specimen from the cell and determine the moisture content (w) of
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