Measurement and Estimation of State Variables - Unsaturated Soil Mechanics in Engineering Practice - page 135

14

c 1

13

12

( a 1 + c 1 ) / 2

11

d 1

10

b 1

a 1

9

8

0 1 10 100 1000 10,000 100,000

Suction, y

Figure 4.41 Variables associated with calibration equation for FTC-100 thermal conductivity
suction sensors (after Hu et al., 2007).

Table 4.5 Calibration Parameters with Shuai et al., (2002) Temperature Correction Applied
to Laboratory-Measured Data

a 1 b 1 c 1 dψ/dT

( ◦ C) ( ◦ C) (kPa/ ◦ C) Sensor (kPa) Power Term

FTC1 9.546 265.197 13.301 187.915 0.665

FTC2 9.466 249.972 13.502 193.114 0.780

FTC3 9.466 251.427 13.683 146.760 0.615

FTC4 8.502 271.992 12.874 200.325 0.805

FTC5 9.111 247.115 13.512 162.070 0.722

FTC6 9.399 284.507 13.720 214.919 0.816

FTC7 9.391 265.434 13.479 199.341 0.768

FTC8 9.284 247.859 13.473 154.341 0.652

FTC9 9.187 272.298 13.184 208.399 0.765

FTC10 9.725 282.024 13.346 237.945 0.764

FTC11 8.708 259.302 12.788 169.213 0.666

FTC12 9.131 263.353 13.158 149.147 0.570

FTC13 9.758 259.571 13.593 207.638 0.767

FTC14 8.995 261.762 13.216 210.067 0.847

FTC15 8.833 263.482 12.928 173.399 0.674

FTC16 8.509 231.937 12.599 145.282 0.640

Maximum value 9.758 284.507 13.720 237.945 0.847

Minimum value 8.502 231.937 12.599 145.282 0.570

Average value 9.188 261.077 13.272 184.992 0.720

Standard deviation 0.394 13.468 0.333 28.374 0.080

Coefficient of variation 4.283 5.159 2.508 15.338 11.169