Geosynthetics April/May 2020 - 20
Construction water flow dynamics of the leak detection layer
0.37000
Sy (lab) = 0.364
0.36500
0.36000
y = 0.3373x0.0149
R² = 0.9695
0.35500
Measured Sy
0.35000
0.34500
Sy
0.34000
0.33500
0.33000
0.32500
0.32000
0
20
40
60
80
100
120
140
Days after LDS Layer Sealed
FIGURE 3 Theoretical curve of specific yield and measured specific yield
350
80
Theoretical Daily Flow
Measured Daily Flow
300
75
Moving Avg Temp
250
200
Daily Flow
(Gallons)
65
150
60
100
55
50
0
50
15
35
55
75
95
Days after LDS Layer Sealed
FIGURE 4 Theoretical curve of flow rate and measured flow rate with
moving average temperature
20
115
135
Temperature (°F)
70
but time dependent as well. In testing for
Sy, most of the water will come out early
on, but there is virtually no limit to how
long the drainage can last. F. H. King, a
pioneer in the study of the time dependence of Sy, tested several columns of sand
for two and one half years. Results of the
coarser sand he evaluated showed that
39.7% of the total drainage occurred during the first 30 minutes, 18.1% occurred
in the second 30 minutes, it took nine
days to drain an additional 32.5%, and the
remaining 9.7% drainage took two and
one half years (King 1899). In order to
expedite laboratory testing, it was found
that if the sample was subjected to 1,000
times the force of gravity, the Sy value
had good agreement with the long-term
value (Johnson et. al 1963). It is now well
established that Sy varies in time. How
Sy is measured in the lab will determine
where the value lands, but the trend over
time will be an exponential curve. The
horizontal asymptote of the curve will be
the final value for Sy if the sample is left to
drain forever. Modern laboratory values of
Sy are typically determined by subjecting
the sample to -850 bar (Stephens 1996).
In light of this, Giroud's equations
were revisited, but instead of solving for
flow and seeing if it matched what was
measured, the measured daily flow was
used to solve for Sy over time. The result
was a logarithmic curve that matched the
textbook curve of Sy over time. The variation between the measured curve and
theoretical curve can be attributed to site
conditions, especially temperature. Each
day, as a little more flow is measured, the
overall Sy gets slightly higher. Each day
the flow is less (on average), raising the Sy
a little bit less each time, until it reaches
infinitely close to the limit of the curve,
in this case the laboratory value of Sy
(0.364). This value is shown as the horizontal asymptote in Figure 3. Note that
leakage was not measured until two weeks
after the LDS layer was sealed. Therefore,
Geosynthetics | April May 2020
0420GS_p16-23.indd 20
3/24/20 12:26 AM
Geosynthetics April/May 2020
Table of Contents for the Digital Edition of Geosynthetics April/May 2020
Geosynthetics April/May 2020 - Cover1
Geosynthetics April/May 2020 - Cover2
Geosynthetics April/May 2020 - 1
Geosynthetics April/May 2020 - 2
Geosynthetics April/May 2020 - 3
Geosynthetics April/May 2020 - 4
Geosynthetics April/May 2020 - 5
Geosynthetics April/May 2020 - 6
Geosynthetics April/May 2020 - 7
Geosynthetics April/May 2020 - 8
Geosynthetics April/May 2020 - 9
Geosynthetics April/May 2020 - 10
Geosynthetics April/May 2020 - 11
Geosynthetics April/May 2020 - 12
Geosynthetics April/May 2020 - 13
Geosynthetics April/May 2020 - 14
Geosynthetics April/May 2020 - 15
Geosynthetics April/May 2020 - 16
Geosynthetics April/May 2020 - 17
Geosynthetics April/May 2020 - 18
Geosynthetics April/May 2020 - 19
Geosynthetics April/May 2020 - 20
Geosynthetics April/May 2020 - 21
Geosynthetics April/May 2020 - 22
Geosynthetics April/May 2020 - 23
Geosynthetics April/May 2020 - 24
Geosynthetics April/May 2020 - 25
Geosynthetics April/May 2020 - 26
Geosynthetics April/May 2020 - 27
Geosynthetics April/May 2020 - 28
Geosynthetics April/May 2020 - 29
Geosynthetics April/May 2020 - 30
Geosynthetics April/May 2020 - 31
Geosynthetics April/May 2020 - 32
Geosynthetics April/May 2020 - 33
Geosynthetics April/May 2020 - 34
Geosynthetics April/May 2020 - 35
Geosynthetics April/May 2020 - 36
Geosynthetics April/May 2020 - 37
Geosynthetics April/May 2020 - 38
Geosynthetics April/May 2020 - 39
Geosynthetics April/May 2020 - 40
Geosynthetics April/May 2020 - 41
Geosynthetics April/May 2020 - 42
Geosynthetics April/May 2020 - 43
Geosynthetics April/May 2020 - 44
Geosynthetics April/May 2020 - 45
Geosynthetics April/May 2020 - 46
Geosynthetics April/May 2020 - 47
Geosynthetics April/May 2020 - 48
Geosynthetics April/May 2020 - 49
Geosynthetics April/May 2020 - 50
Geosynthetics April/May 2020 - 51
Geosynthetics April/May 2020 - 52
Geosynthetics April/May 2020 - 53
Geosynthetics April/May 2020 - 54
Geosynthetics April/May 2020 - 55
Geosynthetics April/May 2020 - 56
Geosynthetics April/May 2020 - 57
Geosynthetics April/May 2020 - 58
Geosynthetics April/May 2020 - 59
Geosynthetics April/May 2020 - 60
Geosynthetics April/May 2020 - Cover3
Geosynthetics April/May 2020 - Cover4
https://www.nxtbook.com/ata/geosynthetics/geosynthetics-april-may-2024
https://www.nxtbook.com/ata/geosynthetics/geosynthetics-february-march-2024
https://www.nxtbook.com/ata/geosynthetics/geosynthetics-december-2023-january-2024
https://www.nxtbook.com/ata/geosynthetics/geosynthetics-october-november-2023
https://www.nxtbook.com/ata/geosynthetics/geoysynthetics-august-september-2023
https://www.nxtbook.com/ata/geosynthetics/geosynthetics-june-july-2023
https://www.nxtbook.com/ata/geosynthetics/geosynthetics-april-may-2023
https://www.nxtbook.com/ata/geosynthetics/geosynthetics-february-march-2023
https://www.nxtbook.com/ata/geosynthetics/geosynthetics-december-2022-january-2023
https://www.nxtbook.com/ata/geosynthetics/geosynthetics-october-november-2022
https://www.nxtbook.com/ifai/geosynthetics/geosynthetics-august-september-2022
https://www.nxtbook.com/ifai/geosynthetics/geosynthetics-june-july-2022
https://www.nxtbook.com/ifai/geosynthetics/geosynthetics-april-may-2022
https://www.nxtbook.com/ifai/geosynthetics/geosynthetics-february-march-2022
https://www.nxtbook.com/ifai/geosynthetics/geosynthetics-december-2021-january-2022
https://www.nxtbook.com/ifai/geosynthetics/geosynthetics-october-november-2021
https://www.nxtbook.com/ifai/geosynthetics/geosynthetics-august-september-2021
https://www.nxtbook.com/ifai/geosynthetics/geosynthetics-june-july-2021
https://www.nxtbook.com/ifai/geosynthetics/geosynthetics-april-may-2021
https://www.nxtbook.com/ifai/geosynthetics/geosynthetics-february-march-2021
https://www.nxtbook.com/ifai/geosynthetics/1220GS
https://www.nxtbook.com/ifai/geosynthetics/1020GS
https://www.nxtbook.com/ifai/geosynthetics/0820GS
https://www.nxtbook.com/ifai/geosynthetics/0620GS
https://www.nxtbook.com/ifai/geosynthetics/0420GS
https://www.nxtbook.com/ifai/geosynthetics/0220GS
https://www.nxtbook.com/ifai/geosynthetics/1219GS
https://www.nxtbook.com/ifai/geosynthetics/1019GS
https://www.nxtbook.com/ifai/geosynthetics/0819GS
https://www.nxtbook.com/ifai/geosynthetics/0619GS
https://www.nxtbook.com/ifai/geosynthetics/0419GS
https://www.nxtbook.com/ifai/geosynthetics/0219GS
https://www.nxtbook.com/ifai/geosynthetics/1218GS
https://www.nxtbook.com/ifai/geosynthetics/1018GS
https://www.nxtbook.com/ifai/geosynthetics/0818GS
https://www.nxtbook.com/ifai/geosynthetics/0618GS
https://www.nxtbook.com/ifai/geosynthetics/0418GS
https://www.nxtbook.com/ifai/geosynthetics/0218GS
https://www.nxtbookmedia.com