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` D 3385 Mariotte tubes. As soon as the fluid level becomes basically 9.1.2 For the annular space between rings calculate as rs constant, determine the fluid depth in the inner ring and in the follows: annular space to the nearest 2 mm('/16 in.)using antler or tape VA=AVA1(AA'U (2) measure.Record these depths. If the depths between the inner ring and annular space varies more than 5 mm(t/4 in.),raise the where: depth gage,constant-level float valve, or Mariotte tube having VA = annular space incremental infiltration velocity, the shallowest depth. cam• 8.6.7 Maintain the liquid level at the selected head in both AV,, = volume of liquid used during time interval to t. the inner ring and annular space between rings as near as maintain constant head in the annular space be- possible throughout the test, to prevent flow of fluid from one tween the rings, cm3, and ring to the other. AA = area of annular space between the rings, cmZ. Nare 6—This most likely will require either a continuing adjustment of 10. Report the flow control valve on the graduated cylinder,or the use of constant- level float valves.A rapid change in temperature may eliminate use of the 10.1 Report the following information in the report or field Mariotte tube. records, or both: 8.7 Measurements: 10.1.1 location of test site. 8.7.1 Record the ground temperature at a depth of about 300 10.1.2 Dates of test, start and.finish. 10.1.3 Weather conditions, start to finish. mm(12 et or n the mid-depthrcorda the test zone. 10.1.4 Name(s)of technician(s). � 8.7.2 Determine and record the volume of liquid that is added to maintain a constant head in the inner ring and annular 10.1.5 Description of test site, including boring profile, see space during each timing interval by measuring the change in 10.1.11. elevation of liquid level in the appropriate graduated cylinder 10.1.6 Type of liquid used in the test,along with the liquid's or Mariotte tube. Also, record the temperature of the liquid pH. If available, a full analysis of the liquid also should be within the inner ring, recorded. 8.7.3 For average soils, record the volume of liquid used at 10.1.7 Areas of rings and the annular space between rings. intervals of 15 min for the first hour, 30 min for the second 10.1.8 Volume constants for graduated cylinders or Mariotte hour,and 60 ruin during the remainder of a period of at least 6 tubes' h, or until after a relatively constant rate is obtained. 10.1.9 Depth of liquid in inner ring and annular space. 8.7.4 The appropriate schedule of readings may be deter- 10.1.10 Record of ground and liquid temperatures, incre- mined only through experience.For high-permeability materi- mental volume measurements, and incremental infiltration als,readings may be more frequent,while for low-permeability velocities (inner ring and annular space) versus elapsed time. materials, the reading interval may be 24 h or more. In any The rate of the inner ring should be the value used if the rates 1 event, the volume of liquid used in any one reading interval for inner ring and annular space differ.The difference in rates should not be less than approximately 25 CM3. is due to divergent flow. i 8.7.5 Place the driving cap or some other covering over the 10.1.11 If available, depth to the water table and a descnp- rings during the intervals between liquid measurements to tion of the soils found between the rings and the water table,or to a depth of about l m 3 h minimize evaporation (see 8.2.1). 10.1 �+ .12 A plot of the incremental infiltration rate versus 8.7.6 Upon completion of the test, remove the rings from the soil,assisted by light hammering on the sides with a rubber total elapsed time(see Fig. 4). t hammer. 10.2 An example field records form is given in Fig. 3. 10.3 See Appendix Xl for information on the determination 9. Calculations of the moisture pattern. 9.1 Convert the volume of liquid used during each measured time interval into an incremental infiltration velocity for both 11. Precision and Bias the inner ring and annular space using the following equations: 11.1 No statement on precision and bias can be made due to 9.1.1 For the inner ring calculate as follows: the variability in soils tested and in the types of liquids that VR=AV,Rt(A,R Ar) (l) might be used in this test method.Because of the many factors related to the soils, as well as the liquids that may affect the where: results,the recorded infiltration rate should be considered only VrR = inner ring incremental infiltration velocity, cm/h, as an index value. AVIR = volume of liquid used during time interval to I maintain constant head in the inner ring, cm3, 12. Keywords AIR = internal area of inner ring, cmZ, and 12.1 coefficient of permeability; hydraulic conductivity; At = time interval, h. infiltration rate; infiltrometer; in-situ testing; Mariotte tube r 376