| Abstrakt: |
This work aimed to study seepage problems in the foundations of barrages containing problematic gypsiferous soil layers as a way to investigate the effects of such soils on hydraulic functions with respect to subsurface flow. Gypsiferous soils are characterised by their higher solubility in contact with water, which can lead to problems underneath the foundations of structures; control devices must thus be constructed to decrease and minimise seepage discharge insofar as possible. These control devices often take the form of cutoff walls upstream (U/S), downstream (D/S), and at an intermediate point, if needed, with protection layers U/S and D/S of the structure. In this study, the control devices used were cutoff walls U/S and D/S and an increased length of impervious floor. The finite element program SEEP/W 2018 R2 was used to calculate the seepage discharge, uplift pressure, and exit gradients beneath a concrete barrage provided with two cutoff walls, U/S and D/S, and the most influential parameters for controlling subsurface flow were found to be the cutoff wall depth upstream, the cutoff wall depth downstream, and the total floor length. The measured parameters showed that increases in cutoff wall depth U/S and D/S led to decreasing seepage rates, with the increase in the total floor length making it clearer when the depth of U/S cutoff increased. Exit gradient was mainly affected by cutoff wall depth D/S, which decreased the exit gradient by increasing its depth with respect to the total floor length. A multiple non-linear regression (MNR). technique was then used to develop hydraulic functions (total seepage flux and exit gradient) for foundations containing gypsiferous soil, and the coefficient of determination (R2) for the derived model for seepage flux and exit gradient showed good correlation between measured parameters, with R2 values of 0.617 and 0.777, respectively. [ABSTRACT FROM AUTHOR] |
