Fig. 4
Four-panel plots showing strain evolution in six fiber segments during the wet-sand experiment. (a) Overview of all three phases—water rise, hold, and drainage—using fiber length vs. strain plots and a waterfall plot for fiber segment #3. Time-lapse variations of fiber length versus strain are shown for the full experiment (0.5 to 234 min) using 25 representative curves. b-d. Expanded views of the individual phases: (b) water rise, (c) water hold, and (d) water drainage. In each phase, the left subpanel displays fiber length vs. strain (horizontal axis: fiber length in mm; vertical axis: strain in µε), while the right subpanel shows the corresponding waterfall plot for fiber segment #3, capturing temporal variations. Colored numbers mark the six fiber segments, and colored letters A–E indicate fiber support points. Strain spikes at O and P are calibration signals produced by manually tapping the fiber at those positions.
