ASTM D4428 D4428M-2014 Standard Test Methods for Crosshole Seismic Testing《井间地震测试用标准试验方法》.pdf
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1、Designation: D4428/D4428M 14Standard Test Methods forCrosshole Seismic Testing1This standard is issued under the fixed designation D4428/D4428M; the number immediately following the designation indicates theyear of original adoption or, in the case of revision, the year of last revision. A number in
2、 parentheses indicates the year of lastreapproval. A superscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope*1.1 These test methods are limited to the determination ofthe velocity of two types of horizontally travelling seismicwaves in soil materials; prim
3、ary compression (P-wave) andsecondary shear (S-wave) waves. The standard assumes thatthe method used to analyze the data obtained is based on firstarrival times or interval arrival times over a measured distance.1.2 Acceptable interpretation procedures and equipment,such as seismic sources, receiver
4、s, and recording systems arediscussed. Other items addressed include borehole spacing,drilling, casing, grouting, deviation surveys, and actual testprocedures.1.3 These test methods are primarily concerned with theactual test procedure, data interpretation, and specifications forequipment which will
5、 yield uniform test results.1.4 All recorded and calculated values shall conform to theguide for significant digits and rounding established in PracticeD6026.1.4.1 The procedures used to specify how data are collected/recorded and calculated in these test methods are regarded asthe industry standard
6、. The procedures used do not considermaterial variation, purpose for obtaining the data, specialpurpose studies, or any considerations for the users objectives.Measurements made to more significant digits or better sensi-tivity than specified in these test methods shall not be regardeda nonconforman
7、ce with this standard.1.5 UnitsThe values stated in either SI units or inch-pound units presented in brackets are to be regarded sepa-rately as standard. The values stated in each system may not beexact equivalents; therefore, each system shall be used inde-pendently of the other. Combining values f
8、rom the two systemsmay result in non-conformance with the standard. Reporting oftest results in units other than SI shall not be regarded asnonconformance with this test method.1.6 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsi
9、bility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:D653 Terminology Relating to Soil, Rock, and ContainedFluidsD3740 Practice for Minimum Requireme
10、nts for AgenciesEngaged in Testing and/or Inspection of Soil and Rock asUsed in Engineering Design and ConstructionD6026 Practice for Using Significant Digits in GeotechnicalData3. Terminology3.1 Definitions:3.1.1 For definitions of common technical terms in thisstandard, refer to Terminology D653.3
11、.2 Definitions of Terms Specific to This Standard:3.2.1 seismic wave trainthe recorded motion of a seismicdisturbance with time.4. Summary of Test Method4.1 The Crosshole Seismic Test makes direct measurementsof P-wave velocities, or S-wave velocities, in boreholes ad-vanced primarily through soil.
12、At selected depths down theborehole, a borehole seismic source is used to generate aseismic wave train. Downhole receivers are used to detect thearrival of the seismic wave train in offset borings at arecommended spacing of 3 to 6 m 10 to 20 ft. The distancebetween boreholes at the test depths is me
13、asured using aborehole deviation survey. The borehole seismic source isconnected to and triggers a data recording system that recordsthe response of the downhole receivers, thus measuring thetravel time of the wave train between the source and receivers.1These test methods are under the jurisdiction
14、 of ASTM Committee D18 on Soiland Rock and are the direct responsibility of Subcommittee D18.09 on Cyclic andDynamic Properties of Soils.Current edition approved March 1, 2014. Published April 2014. Originallyapproved in 1984. Last previous edition approved in 2007 as D4428/D4428M 07.DOI: 10.1520/D4
15、428_D4428M-14.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1The P-wave or S-wave velocity is calculated from the mea-sured distance and travel time for the respective
16、wave train.5. Significance and Use5.1 The seismic crosshole method provides a designer withinformation pertinent to the seismic wave velocities of thematerials in question (1).2This data may be used as follows:5.1.1 For input into static/dynamic analyses;5.1.2 For computing shear modulus, Youngs mod
17、ulus, andPoissons ratio (provided density is known or assumed);5.1.3 For determining Seismic Site Class using the appro-priate Building Code; and5.1.4 For assessing liquefaction potential.5.2 Fundamental assumptions inherent in the test methodsare as follows:5.2.1 Horizontal layering is assumed.5.2.
18、2 Snells law of refraction applies to P-waves andS-waves and to the velocities derived from crosshole tests. IfSnells law of refraction is not considered in the analysis ofCrosshole seismic testing data, the report shall so state, and theP-wave and S-wave velocities obtained may be unreliable forcer
19、tain depth intervals near changes in stratigraphy (2).NOTE 1The quality of the results produced by these test methods isdependent on the competence of the personnel performing it and thesuitability of the equipment and facilities. Agencies that meet the criteriaof Practice D3740 are generally consid
20、ered capable of competent andobjective testing/sampling/inspection and so forth. Users of these testmethods are cautioned that compliance with Practice D3740 does not initself assure reliable results. Reliable results depend on many factors;Practice D3740 provides a means of evaluating some of those
21、 factors.6. Apparatus6.1 The basic data acquisition system consists of the fol-lowing:6.1.1 Energy SourcesThe source shall be rich in the typeof energy required, that is, to produce good P-wave data, theenergy source must transmit adequate energy to the medium incompression or volume change. Impulsi
22、ve sources, such asexplosives, hammers, or air guns, are all acceptable P-wavegenerators. To produce an identifiable S-wave, the source shalltransmit energy to the ground primarily by distortion. Verti-cally polarized S-waves (SV) are most commonly measured,but horizontally polarized S-waves are als
23、o very useful. Fig. 1and Fig. 2 show examples of impulse and vibratory seismicsource wave trains respectively. For good S-waves, energysources must be repeatable and, although not mandatory,reversible. The S-wave source must be capable of producing anS-wave train with an amplitude greater than the P
24、-wave train.6.1.2 ReceiversThe receivers intended for use in thecrosshole test shall be transducers having appropriate fre-quency and sensitivity characteristics to determine the seismicwave train arrivals. Typical examples include geophones andaccelerometers. S-waves are typically in the range of 5
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