Asset management is a strategic decision-making aspect of social infrastructure that ensures safety by predicting long-term conditions and maximizing effectiveness under budgetary constraints. Predicting the deterioration of impervious walls is essential in the asset management of coastal landfill sites, particularly in the design of their maintenance and repair strategy. In this paper, a quantitative evaluation of the leakage of toxic substances in coastal landfill sites where deterioration of side impervious walls has decreased the water interception performance is reported. In addition, risk evaluation based on the asset management of the leakage is applied to determine an appropriate repair method. The strategy of repairing the walls when the concentration of the toxic substances leaking into the sea area exceeds the closure and abandonment of coastal landfill sites is demonstrated to be superior. Moreover, the strategy of repairing only the seaside side impervious wall is shown to be cost-effective.
To better understand the effect of fluid distribution on the electric response of rocks saturated with oil and brine, we conducted experimental studies on the complex electrical impedance in a Berea sandstone, together with in situ acquisitions of oil distribution images employing a high‐resolution medical X‐ray computed tomography. We performed two tests of brine displacement by oil under high (10 MPa) and low (5 MPa) pressures, which were accompanied by fingering and stable displacement patterns, respectively. The measured complex impedance data were fitted to the Cole model to obtain the resistance, capacitance, peak frequency of the imaginary impedance, and the exponent α of the rock–fluid system. With increasing oil saturation, the resistance showed an increasing trend, whereas the other three parameters decreased. The fingering displacement exhibited lower resistance and capacitance than the stable displacement. The analysis of the resistance changes using a simple parallel connection model indicates that there are more components of residual brine in parallel connections in the fingering pattern than in the stable displacement pattern at the same saturation. We also interpreted the normalised changes in the capacitance (or apparent dielectric constant) with respect to the oil saturation via an analysis of the shape factor of fluid distribution based on the Maxwell–Wagner–Brugermann–Hanai model. The changes in the shape factor suggest that the pinch‐off of the brine in parallel connection by the oil is a dominant mechanism reducing the capacitance. In the stable displacement, most of the connections in the brine phase are immediately pinched off by oil displacement front at a local oil saturation of 65%. Conversely, in the fingering displacement, there is a transition from the bulk or layered brine to the pinched‐off at a local oil saturation below 60%. The analyses indicate that the difference in the fluid distribution under different fluid conditions is responsible for the non‐Archie behaviour.
The paper deals with water cut-off walls for offshore waste landfill facilities that are used to prevent leakage of toxic substances to the surrounding water. A new type of a widely used water cut-off wall called Steel Pipe Sheet Piles (SPSP) is investigated with experimental measurements as well as numerical simulations. The main objective is to found out the influence of tidal fluctuations in the sea on the outflow of the contaminant and the results show that the outflow of contaminants is lower when tidal fluctuations are present compared to the case with only a mean water level. The influence of different filler materials on this behavior is also investigated.
For the most proper solution of annual increase of solid and other waste treatment in the limited landfill site, the global leading countries develop and keep expanding operation of the offshore waste landfill sites. In this report, we examined the most proper mix ratio of the water cut-off materials for the prevention and enforcement of the performance of the existing cut-off wall inter-connection parts of the offshore waste landfill site, which might be deteriorated by the external force inherent in the sea area. For acquiring the most proper mixed ratios in back-up water cut-off materials, we examined and evaluated the physical characteristics of the applied back-up water cut-off materials — on-site marine clay materials, which might be possible to be acquired near to site, admixtures and bentonite. Also, we applied those back-up water cut-off materials into the new concept applied to the vertical cut-off wall connection parts and investigated variation of the water cut-off performances throughout the changes of the permeability coefficient before and after deformation of the inter-connection joints of the vertical cut-off walls. For the investigation of the permeability performances, we carried out half sized mock-up tests in the laboratory and checked the variation of permeability coefficients referred to the changes in the applying location of back-up water cut-off materials and finally reach to application of back-up water cut-off materials as a proper solution of water cut-off performances in the inter-connection parts of the vertical cut-off wall at offshore waste landfill site.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.