AASHTO T 207-2012 Standard Method of Test for Thin-Walled Tube Sampling of Soils.pdf

1、Standard Method of Test for Thin-Walled Tube Sampling of Soils AASHTO Designation: T 207-121ASTM Designation: D1587-08 American Association of State Highway and Transportation Officials 444 North Capitol Street N.W., Suite 249 Washington, D.C. 20001 TS-1b T 207-1 AASHTO Standard Method of Test for T

2、hin-Walled Tube Sampling of Soils AASHTO Designation: T 207-121ASTM Designation: D1587-08 1. SCOPE 1.1. This method covers a procedure for using a thin-walled metal tube to recover relatively undisturbed soil samples suitable for laboratory tests of engineering properties, such as strength, compress

3、ibility, permeability, and density. Thin-walled tubes used in piston-, plug-, or rotary-type samplers, such as the Denison or Pitcher, must comply with the portions of this practice that describe the thin-walled tubes (Section 5.3). Note 1This method does not apply to liners used within the above sa

4、mplers. 1.2. Not all tubes specified in this method may be of sufficient diameter to perform all strength or consolidation testing. Refer to the appropriate test method for the minimum sample size to determine if the tube will be appropriate for that test. 1.3. The values stated in SI units are to b

5、e regarded as the standard. 1.4. 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 whoever uses this standard to establish appropriate safety and health p

6、ractices and determine the applicability of regulatory limitations prior to use. 2. REFERENCED DOCUMENTS 2.1. AASHTO Standard: R 13, Conducting Geotechnical Subsurface Investigations 2.2. ASTM Standard: D4220, Standard Practices for Preserving and Transporting Soil Samples 3. SUMMARY OF METHOD 3.1.

7、A relatively undisturbed sample is obtained by pressing a thin-walled metal tube into the in situ soil at the bottom of a boring, removing the soil-filled tube, and sealing the ends to prevent the soil from being disturbed or losing moisture. 4. SIGNIFICANCE AND USE 4.1. This method is used when it

8、is necessary to obtain a relatively undisturbed specimen suitable for laboratory tests of engineering properties or other tests that might be influenced by soil disturbance. 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation

9、 of applicable law.TS-1b T 207-2 AASHTO 5. APPARATUS 5.1. Drilling EquipmentAny drilling equipment may be used that provides a reasonably clean hole, that minimizes disturbance of the soil to be sampled, and that does not hinder the penetration of the thin-walled sampler. Open borehole diameter and

10、the inside diameter of driven casing or hollow stem auger shall not exceed 3.5 times the outside diameter of the thin-walled tube. 5.2. Sampler Insertion Equipmentshall be adequate to provide a relatively rapid continuous penetration force. For hard formations it may be necessary, although not recom

11、mended, to drive the thin-walled tube sampler. 5.3. Sampler Headserves to couple the thin-walled tube to the insertion equipment and, together with the thin-walled tube, comprises the thin-walled tube sampler. The sampler head shall contain a suitable check valve and a venting area to the outside eq

12、ual to or greater than the area through the check valve. In some special cases, a check valve may not be required, but venting is required to avoid sample compression. Attachment of the head to the tube shall be concentric and coaxial to assure uniform application of force to the tube by the sampler

13、 insertion equipment. 5.4. Thin-Walled Tubesshould be manufactured as shown in Figure 1. They should have an outside diameter of 50.8 to 127.0 mm (2 to 5 in.) and be made of metal having adequate strength for use in the soil and formation intended. Tubes shall be clean and free of all surface irregu

14、larities including projecting weld seams. Other diameters may be used, but the tube dimensions should be proportional to the tube designs presented here. English Equivalents mm in. 9.52 3/812.7 1/225.4 1 50.8 2 88.9 31/2101.6 4 Figure 1Thin-Walled Tube for Sampling 2015 by the American Association o

15、f State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-1b T 207-3 AASHTO 5.4.1. Length of TubesSee Table 1 and Section 6.4. 5.4.2. Tolerancesshall be within the limits shown in Table 2. 5.4.3. Inside Clearance Ratioshould not be greater than

16、 1 percent or as specified by the engineer or geologist for the soil and formation to be sampled. Generally, the inside clearance ratio used should increase with the increase in plasticity of the soil being sampled, except for sensitive soils or where local experience indicates otherwise. See Figure

17、 1 for definition of inside clearance ratio. Table 1Suitable Thin-Walled Steel Sample TubesaOutside diameter: mm 50.8 76.2 127.0 in. 2 3 5 Wall thickness: BWG 18 16 11 mm 1.24 1.65 3.05 in. 0.049 0.065 0.120 Tube length: m 0.91 0.91 1.37 in. 36 36 54 Clearance: ratio, percent 1 1 1 aThe three diamet

18、ers recommended in Table 1 are indicated for purposes of standardization and are not intended to indicate that sampling tubes of intermediate or larger diameters are not acceptable. Lengths of tubes shown are illustrative. Proper lengths to be determined as suited to field conditions. Table 2Dimensi

19、onal Tolerances for Thin-Walled Tubes Nominal Tube Diameters from Table 1aTolerances Size Outside Diameter, mm 50.8 76.2 127 in. (2) (3) (5) Outside diameter: mm +0.18 +0.25 +0.38 in. (+0.007) (+0.010) (+0.015) mm 0.00 0.00 0.00 in. (0.000) (0.000) (0.000) Inside diameter: mm +0.00 +0.00 +0.00 in. (

20、+0.000) (+0.000) (+0.000) mm 0.18 0.25 0.38 in. (0.007) (0.010) (0.015) Wall thickness: mm 0.18 0.25 0.38 in. (0.007) (0.010) (0.015) Ovality:bmm 0.38 0.51 0.76 in. (0.015) (0.020) (0.030) Straightness: mm/m 2.5 2.5 2.5 in./ft (0.030) (0.030) (0.030) aIntermediate or larger diameters should be propo

21、rtional. Tolerances shown are essentially standard commercial manufacturing tolerances for seamless steel mechanical tubing. Specify only two of the first three tolerances: that is, OD and ID, or OD and Wall, or ID and Wall. bOvalitythe cross section of the tube that deviates from a perfect circle.

22、2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-1b T 207-4 AASHTO 5.4.4. Corrosion ProtectionCorrosion, whether from galvanic or chemical reaction, can damage or destroy both the thin-walled tube and

23、the sample. Severity of damage is a function of time as well as interaction between the sample and the tube. Thin-walled tubes should have some form of protective coating. Tubes that will contain samples for more than 72 h shall be coated. The type of coating to be used may vary depending upon the m

24、aterial to be sampled. Coatings may include a light coat of lubricating oil, lacquer, epoxy, Teflon, and others. Type of coating must be specified by the engineer or geologist if storage will exceed 72 h. Plating of the tubes or alternate base metals may be specified by the engineer or geologist. 6.

25、 PROCEDURE 6.1. Advance the borehole using methods outlined in R 13. Clean out the borehole to sampling elevation using whatever method is preferred that will ensure the material to be sampled is not disturbed. If groundwater is encountered, maintain the liquid level in the borehole at or above grou

26、ndwater level during the sampling operation. 6.2. Bottom discharge bits are not permitted. Side discharge bits may be used, with caution. Jetting through an open-tube sampler to clean out the borehole to sampling elevation is not permitted. Remove loose material from the center of a casing or hollow

27、 stem auger as carefully as possible to avoid disturbance of the material to be sampled. Note 2Roller bits are available in downward-jetting and diffused-jet configurations. Downward-jetting configuration rock bits are not acceptable. Diffuse-jet configurations are generally acceptable. 6.3. Place t

28、he sample tube so that its bottom rests on the bottom of the hole. Record the depth to the bottom of the sample tube to the nearest 0.3 m (0.1 ft). Advance the sampler without rotation by a continuous, relatively rapid motion. 6.4. Determine the length of advance by the resistance and condition of t

29、he formation, but the length shall never exceed 5 to 10 diameters of the tube in sands and 10 to 15 diameters of the tube in clays. Note 3The mass of the sample, laboratory-handling capabilities, transportation problems, and commercial availability of tubes will generally limit maximum practical len

30、gths to those shown in Table 1. 6.5. When the formation is too hard for push-type insertion, the tube may be driven. Other methods, as directed by the engineer or geologist, may be used. If driving methods are used, the data regarding mass and fall of the hammer and penetration achieved must be show

31、n in the report. Additionally, that tube must be prominently labeled a “driven sample.” 6.6. In no case shall a length of advance be greater than the sample-tube length minus an allowance for the sampler head and a minimum of 76.2 mm (3 in.) for sludge-end cuttings. Note 4The tube may be rotated to

32、shear bottom of the sample after pressing is complete. 6.7. Withdraw the sampler from the formation as carefully as possible in order to minimize disturbance of the sample. Where the soil formation is soft, a delay before withdraw of the sampler (typically 5 to 30 min) may improve sample recovery. 7

33、. PREPARATION FOR SHIPMENT 7.1. Upon removal of the tube, measure the length of sample in the tube. Remove the drill cuttings in the upper end of the tube and measure the length again. Seal the upper end of the tube. Remove at least 25 mm (1 in.) of material from the lower end of the tube. Use this

34、material for soil 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-1b T 207-5 AASHTO description. Measure the overall sample length. Seal the lower end of the tube. Alternatively, after measurement, th

35、e tube may be sealed without removal of soil from the ends of the tube, if so directed by the engineer or geologist. Note 5Field extrusion and packaging of extruded samples under the specific direction of a geotechnical engineer or geologist is permitted. Samples are extruded in special hydraulic ja

36、cks equipped with properly sized platens to extrude the core in a continuous smooth speed. Bent or damaged tubes should be cut off before extruding. Note 6Tubes sealed over the ends as opposed to those sealed with expanding packers should contain end padding in end voids in order to prevent drainage

37、 or movement of the sample within the tube. 7.2. Prepare and immediately affix labels or apply markings as necessary to identify the sample. Assure that the markings or labels are adequate to survive transportation and storage. 7.3. The method of care and handling of tube samples during shipment can

38、 affect the integrity or degree to which the samples remain undisturbed and suitable for laboratory testing. Tubes should be stored and transported in a vertical position, protected from extreme heat and cold, and protected from vibration and shock. Additional guidance on the care and transportation

39、 of tube samples is provided in ASTM D4220. Note 7The top end of the tube should be labeled “TOP.” 8. REPORT 8.1. The appropriate information on the field log is required as follows: 8.1.1. Name and location of the project; 8.1.2. Boring number and precise location on project; 8.1.3. Surface elevati

40、on or reference to a datum; 8.1.4. Date and time of boringstart and finish; 8.1.5. Depth to top of sample and number of sample; 8.1.6. Description of sampler: size, type of metal, type of coating; 8.1.7. Method of sampler insertionpush or drive; 8.1.8. Method of drilling, size of hole, casing, and d

41、rilling fluid used; 8.1.9. Depth to groundwater leveldate and time measured; 8.1.10. Any possible current or tidal effect on water level; 8.1.11. Soil description; 8.1.12. Length of sampler advance; and 8.1.13. Recovery: length of sample obtained. 2015 by the American Association of State Highway an

42、d Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-1b T 207-6 AASHTO 9. PRECISION AND BIAS 9.1. This method does not produce numerical data; therefore, a precision and bias statement is not applicable. 1Except for the use of SI units, this method is technically equivalent to ASTM D1587-08. 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.