Abstract
Design parameters typically used for the mineral liner of landfill cover system (e.g. water content w, dry density ρd and hydraulic conductivity k) are often difficult to obtain on site. After construction, these experimental parameters need to be checked against the predicted values. In this paper, a rigorous procedure for design, construction and control of a compacted mineral liner in a capping multilayer system has been developed. The procedure has been schematically subdivided in three phases. The first phase (design) was based on a wide preliminary set of laboratory tests, composed of classification, compaction and permeability tests. An analytical relationship among degree of saturation Sr, dry density ρd and hydraulic conductivity k is also defined. The second phase (construction) was developed through a suitable compaction of the mineral liner planned after the design phase. The last phase (in-site control) consists of checking the design parameters (w, Sr, ρd, k) actually achieved on site. A comparison between coefficients k, obtained through site permeability tests and an analytical relationship obtained in the design phase, was made successfully. Owing to this new approach, it will no longer be necessary to perform in situ permeability tests, but it will be enough to define the above-mentioned analytical relationship during the design phase. In this way, a dangerous damage to the mineral liner, caused by the execution of invasive permeability tests, will be also avoided.
Highlights
Mineral barriers of municipal solid waste (MSW) landfills extend on very large areas, in the order of tens of hectares
The excavated soil was subjected to laboratory tests to assess the suitability of the soil to be used for compacted mineral liners and to define the design procedure in order to fulfil the requirements of the national regulations in terms of hydraulic conductivity
In order to carry out a further check of the liner permeability a small portion of the compacted mineral liner was made1 m thick and a new set of two stage borehole (TSB) [2, 17,18,19] was performed with Boutwell permeameter (Fig. 12)
Summary
Mineral barriers of municipal solid waste (MSW) landfills extend on very large areas, in the order of tens of hectares. According to national standards [1], mineral barriers must have a minimum thickness of 0.5 m and a maximum hydraulic conductivity of 1 0−8 m/s. The latter is a difficult standard to achieve in the field because of the construction procedure and the very high compressibility of the below wastes. The water content and dry density are checked, while the hydraulic conductivity is estimated using laboratory relationship with the water content. This approach assumes equal compaction energy in the field and laboratory.
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callMore From: International Journal of Geosynthetics and Ground Engineering
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
