1、Standard Method of Test for Penetration Test and Split-Barrel Sampling of Soils AASHTO Designation: T 206-09 (2013)1ASTM Designation: D1586-11 American Association of State Highway and Transportation Officials 444 North Capitol Street N.W., Suite 249 Washington, D.C. 20001 TS-1b T 206-1 AASHTO Stand
2、ard Method of Test for Penetration Test and Split-Barrel Sampling of Soils AASHTO Designation: T 206-09 (2013)1ASTM Designation: D1586-11 1. SCOPE 1.1. This test method describes the procedure, generally known as the Standard Penetration Test (SPT), for driving a split-barrel sampler to obtain a rep
3、resentative soil sample and a measure of the resistance of the soil to penetration of the sampler. 1.2. This standard may involve hazardous materials, operations, and equipment. This standard does not purport to address all of the safety concerns associated with its use. It is the responsibility of
4、the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For a specific precautionary statement, see Section 5.4.1. 1.3. The values stated in SI units are to be regarded as the standard. Note 1ASTM D4633 ca
5、n be used for measuring the energy that enters the drill rod string during testing due to the hammer impact. Note 2ASTM D6066 can be used when testing loose sands below the water table for liquefaction studies or when a higher level of care is required when drilling these soils. This practice provid
6、es information on drilling methods, equipment variables, energy corrections, and blow-count normalization. 2. REFERENCED DOCUMENTS 2.1. AASHTO Standard: R 13, Conducting Geotechnical Subsurface Investigations 2.2. ASTM Standards: D4633, Standard Test Method for Energy Measurement for Dynamic Penetro
7、meters D6066, Standard Practice for Determining the Normalized Penetration Resistance of Sands for Evaluation of Liquefaction Potential 3. TERMINOLOGY 3.1. Description of Terms Specific to This Standard: 3.1.1. anvilthat portion of the drive-weight assembly that the hammer strikes and through which
8、the hammer energy passes into the drill rods. 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-1b T 206-2 AASHTO 3.1.2. catheadthe rotating drum or windlass in the rope-cathead lift system around which
9、 the operator wraps a rope to lift and drop the hammer by successively tightening and loosening the rope turns around the drum. 3.1.3. drill rodsrods used to transmit downward force and torque to the drill bit while drilling a borehole. 3.1.4. drive-weight assemblya device consisting of the hammer,
10、hammer fall guide, the anvil, and any hammer drop system. 3.1.5. hammerthat portion of the drive-weight assembly consisting of the 63.5 1 kg (140 2 lb) impact weight that is successfully lifted and dropped to provide the energy that accomplishes the sampling and penetration. 3.1.6. hammer drop syste
11、mthat portion of the drive-weight assembly by which the operator accomplishes the lifting and dropping of the hammer to produce the blow. 3.1.7. hammer fall guidethat part of the drive-weight assembly used to guide the fall of the hammer. 3.1.8. N-valuethe blow count representation of the penetratio
12、n resistance of the soil. The N-value, reported in blows per foot, equals the sum of the number of blows required to drive the sampler over the depth interval of 150 to 450 mm (6 to 18 in.). (See Section 7.3.) 3.1.9. Nthe number of blows obtained from each of the 150-mm (6-in.) intervals of sampler
13、penetration. (See Section 7.3.) 3.1.10. number of rope turnsthe total contact angle between the rope and the cathead at the beginning of the operators rope slackening to drop the hammer, divided by 360 degrees. (See Figure 1.) 2015 by the American Association of State Highway and Transportation Offi
14、cials.All rights reserved. Duplication is a violation of applicable law.TS-1b T 206-3 AASHTO Figure 1Definitions of the Number of Rope Turns and the Angle for (a) Counterclockwise Rotation and (b) Clockwise Rotation of the Cathead 3.1.11. sampling rodsrods that connect the drive-weight assembly to t
15、he sampler. Drill rods are often used for this purpose. 3.1.12. SPTabbreviation for Standard Penetration Test, a term by which engineers commonly refer to this method. 4. SIGNIFICANCE AND USE 4.1. This test method provides a soil sample for identification purposes and for laboratory tests appropriat
16、e for soil obtained from a sampler that may produce large shear strain disturbance in the sample. 4.2. This test method is used extensively in a great variety of geotechnical exploration projects. Many local correlations and widely published correlations, which relate SPT blow count, or N-value, and
17、 the engineering behavior of earthworks and foundations, are available. 5. APPARATUS 5.1. Drilling EquipmentAny drilling equipment that provides at the time of sampling a suitably clean open hole before insertion of the sampler and ensures that the penetration test is performed on 2015 by the Americ
18、an Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-1b T 206-4 AASHTO undisturbed soil shall be acceptable. The following pieces of equipment have proven to be suitable for advancing a borehole in some subsurface condition
19、s: 5.1.1. Drag, Chopping, and Fishtail Bits, less than 162 mm (6.5 in.) and greater than 56 mm (2.2 in.) in diameter may be used in conjunction with open-hole rotary drilling or casing-advancement drilling methods. To avoid disturbing the underlying soil, bottom discharge bits are not permitted; onl
20、y side discharge bits are permitted. 5.1.2. Roller-Cone Bits, less than 162 mm (6.5 in.) and greater than 56 mm (2.2 in.) in diameter may be used in conjunction with open-hole rotary drilling or casing-advancement drilling methods if the drilling fluid discharge is deflected. 5.1.3. Hollow-Stem Cont
21、inuous Flight Augers, with or without a center bit assembly, may be used to drill the boring. The inside diameter of the hollow-stem augers shall be less than 162 mm (6.5 in.) and greater than 56 mm (2.2 in.). 5.1.4. Solid, Continuous Flight, Bucket, and Hand Augers, less than 162 mm (6.5 in.) and g
22、reater than 56 mm (2.2 in.) in diameter may be used if the soil on the side of the boring does not cave onto the sampler or sampling rods during sampling. 5.2. Sampling RodsFlush-joint steel drill rods shall be used to connect the split-barrel sampler to the drive-weight assembly. The sampling rod s
23、hall have a stiffness (moment of inertia) equal to or greater than that of parallel wall “A” rod (a steel rod that has an outside diameter of 41.2 mm (15/8in.) and an inside diameter of 28.5 mm (11/8in.). Note 3Recent research and comparative testing indicates the type of rod used, with stiffness ra
24、nging from “A” size rod to “N” size rod, will usually have a negligible effect on the N-values to depths of at least 30 m (100 ft). 5.3. Split-Barrel SamplerThe sampler shall consist of a heat-treated, case-hardened, steel head, split spoon and shoe assembly, constructed to the dimensions indicated
25、in Figure 2. The driving shoe shall be of hardened steel and shall be replaced or repaired when it becomes dented or distorted. The use of liners to produce a constant inside diameter of 35 mm (13/8in.) is permitted, but shall be noted on the penetration record if used. The use of a sample retainer
26、basket is permitted, and should also be noted on the penetration record if used. 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-1b T 206-5 AASHTO Note: The 11/2-in. (38-mm) inside diameter split barr
27、el may be used with a 16-gauge wall thickness split liner. The penetrating end of the drive shoe may be slightly rounded. Metal or plastic retainers may be used to retain soil samples. Figure 2Split-Barrel Sampler Note 4Both theory and available test data suggest that N-values may increase between 1
28、0 to 30 percent when liners are used. 5.4. Drive-Weight Assembly: 5.4.1. Hammer and AnvilThe hammer shall weigh 63.5 1 kg (140 2 lb) and shall be a solid rigid metallic mass. The hammer shall strike the anvil and make steel-on-steel contact when it is dropped. A hammer fall guide permitting a free f
29、all shall be used. Hammers used with the cathead and rope method shall have an unimpeded overlift capacity of at least 100 mm (4 in.). For safety reasons, the use of a hammer assembly with an internal anvil is encouraged. Note 5It is suggested that the hammer fall guide be permanently marked to enab
30、le the operator or inspector to judge the hammer drop height. 5.4.2. Hammer Drop SystemRope-cathead, trip, semiautomatic, or automatic hammer drop systems may be used, providing the lifting apparatus will not cause penetration of the sampler while re-engaging and lifting the hammer. 5.5. Accessory E
31、quipmentAccessories such as labels, sample containers, data sheets, and groundwater level measuring devices shall be provided in accordance with the requirements of the project and other ASTM standards. 6. DRILLING PROCEDURE 6.1. The boring shall be advanced incrementally, using methods outlined in
32、R 13, to permit intermittent or continuous sampling. Test intervals and locations are normally stipulated by the project engineer or geologist. Typically, the intervals selected are 1.5 m (5 ft) or less in homogeneous strata with test and sampling locations at every change of strata. 2015 by the Ame
33、rican Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-1b T 206-6 AASHTO 6.2. Any drilling procedure that provides a suitably clean and stable hole before insertion of the sampler and assures that the penetration test is p
34、erformed on essentially undisturbed soil shall be acceptable. Each of the following procedures has proven to be acceptable for some subsurface conditions. The subsurface conditions anticipated should be considered when selecting the drilling method to be used. 6.2.1. Open-hole rotary drilling method
35、. 6.2.2. Continuous flight hollow-stem auger method. 6.2.3. Wash boring method. 6.2.4. Continuous flight solid auger method. 6.3. Several drilling methods produce unacceptable borings. The process of jetting through an open tube sampler and then sampling when the desired depth is reached shall not b
36、e permitted. The continuous flight solid auger method shall not be used for advancing the boring below a water table or below the upper confining bed of a confined noncohesive stratum that is under artesian pressure. Casing may not be advanced below the sampling elevation prior to sampling. Advancin
37、g a boring with bottom discharge bits is not permissible. It is not permissible to advance the boring for subsequent insertion of the sampler solely by means of previous sampling with the SPT sampler. 6.3.1. The sampler head is vented to prevent pressure buildup during sampling, and must be kept cle
38、an. A steel ball water check is located in the head to prevent downward water pressure from acting on the sample. Clogging of the air vents or removal of the water check frequently causes sample loss. 6.4. The drilling fluid level within the boring or hollow-stem augers shall be maintained at or abo
39、ve the in situ groundwater level at all times during drilling, removal of drill rods, and sampling. 7. SAMPLING AND TESTING PROCEDURE 7.1. After the boring has been advanced to the desired sampling elevation and excessive cuttings have been removed, prepare for the test with the following sequence o
40、f operations: 7.1.1. Attach the split-barrel sampler to the sampling rods and lower into the borehole. Do not allow the sampler to drop onto the soil to be sampled. 7.1.2. Position the hammer above and attach the anvil to the top of the sampling rods. This may be done before the sampling rods and sa
41、mpler are lowered into the borehole. 7.1.3. Rest the dead weight of the sampler, rods, anvil, and drive weight on the bottom of the boring and apply a seating blow. If excessive cuttings are encountered at the bottom of the boring, remove the sampler and sampling rods from the boring and remove the
42、cuttings. 7.1.4. Mark the drill rods in three successive 0.15-m (6-in.) increments so that the advance of the sampler under the impact of the hammer can be easily observed for each 0.15-m (6-in.) increment. 7.2. Drive the sampler with blows from the 63.5-kg (140-lb) hammer and count the number of bl
43、ows applied in each 0.15-m (6-in.) increment until one of the following occurs: 7.2.1. A total of 50 blows have been applied during any one of the three 0.15-m (6-in.) increments described in Section 7.1.4. 2015 by the American Association of State Highway and Transportation Officials.All rights res
44、erved. Duplication is a violation of applicable law.TS-1b T 206-7 AASHTO 7.2.2. A total of 100 blows have been applied. 7.2.3. There is no observed advance of the sampler during the application of 10 successive blows of the hammer. 7.2.4. The sampler is advanced the complete 0.45 m (18 in.) without
45、the limiting blow counts occurring as described in Sections 7.2.1, 7.2.2, or 7.2.3. 7.3. Record the number of blows required to effect each 0.15 m (6 in.) of penetration or fraction thereof. The first 6 in. is considered to be a seating drive. The sum of the number of blows required for the second a
46、nd third 6 in. of penetration is termed the “standard penetration resistance,” or the “N-value.” If the sampler is driven less than 0.45 m (18 in.), as permitted in Sections 7.2.1, 7.2.2, or 7.2.3, the number of blows per each complete 0.15-m (6-in.) increment and per each partial increment shall be
47、 recorded on the boring log. For partial increments, the depth of penetration shall be reported to the nearest 25 mm (1 in.), in addition to the number of blows. If the sampler advances below the bottom of the boring under the static weight of the drill rods or the weight of the drill rods plus the
48、static weight of the hammer, this information should be noted on the boring log. 7.4. The raising and dropping of the 63.5-kg (140-lb) hammer shall be accomplished using either of the following two methods: 7.4.1. By using a trip, automatic, or semiautomatic hammer drop system that lifts the 63.5-kg
49、 (140-lb) hammer and allows it to drop 0.76 m 25 mm (30 1.0 in.) unimpeded. 7.4.2. By using a cathead to pull a rope attached to the hammer. When the cathead and rope method is used, the system and operation shall conform to the following: 7.4.2.1. The cathead shall be essentially free of rust, oil, or grease and have a diameter in the range of 150 to 250 mm (6 to 10 in.). 7.4.2.2. The cathead should be operated at a minimum speed of rotation of 100 RPM, or the approximate speed of rotation shall be reported on the boring log. 7.4.2.3. N
