1,720,977 research outputs found
Kinematic interface friction for geosynthetic liner on landfill slopes
No full textThe correct assessment of the interfacial properties between the geosynthetic surfaces in composite liner systems, as landfill covers, is an important issue to prevent the occurrence of potential slip surfaces. To characterize the geosynthetic friction, the Inclined Plane is recognized as a very suitable and versatile device, since it allows testing large samples with variable relative tangential displacements under low normal stress. According to recent studies, the test procedure, ruled by the European Standard EN ISO 12957-2 does not take into the account the real kinematic condition existing during the test. For this reason, two alternative procedures are proposed: the “Displacement Procedure” and the “Force Procedure”. In this study a full description of the three procedures is presented and an application to typical landfill barrier interfaces is carried out. Furthermore, several values of the interface friction angles are determined from the alternative methods and a comparison with the “standard” values is provided
Correlation between compressibility and degradation for a PTMB waste
No full textSettlement of Municipal Solid Waste (MSW) in landfill is a geotechnical key concern since it could lead to dramatic failure of cap cover systems. On the other hand recent research developments demonstrate that it is possible to propose robust relationship between secondary settlement and kinetics of biodegradation. It is a matter of fact that settlement could be divided into two quasi-independent fractions, a classical time-dependent mechanical contribution, similar to the creep phenomenon for cohesive soils, and a biodegradation contribution. There is a practical interest in this finding: settlement monitored at the surface of the landfill cap cover could be considered as a relevant indicator of the biodegradation level. This is specifically interesting in the case of a landfill bioreactive cell, where the influence of leachate injection in this way could be assessed. The present proposal includes two parts: a presentation of the bio-mechanical relationship through the relation between biogas production and compressibility, and an application to mono-directional (oedometer) tests on MSW
Correlation between compressibility and degradation for a PTMB waste
No full textSettlement of Municipal Solid Waste (MSW) in landfill is a geotechnical key concern since it could lead to dramatic failure of cap cover systems. On the other hand recent research developments demonstrate that it is possible to propose robust relationship between secondary settlement and kinetics of biodegradation. It is a matter of fact that settlement could be divided into two quasi-independent fractions, a classical time-dependent mechanical contribution, similar to the creep phenomenon for cohesive soils, and a biodegra-dation contribution.
There is a practical interest in this finding: settlement monitored at the surface of the landfill cap cover could be considered as a relevant indicator of the biodegradation level. This is specifically interesting in the case of a landfill bioreactive cell, where the influence of leachate injection in this way could be assessed.
The present proposal includes two parts: a presentation of the bio-mechanical relationship through the rela-tion between biogas production and compressibility, and an application to mono-directional (oedometer) tests on MSW
Improvement of the hydraulic conductivity of a landfill cap cover for a low activity nuclear waste by bentonite treatment
No full textRelation between settlements and pre-treatment for MSW from laboratory tests.
No full textThis paper focuses on the bio-mechanical analysis of the waste behaviour, based on the results of laboratory tests carried out by means of bio-reactors. For this purpose an original waste and the same waste after pre-treatment were used. The experiments were carried out using two parallel reactor cells, one at the laboratory of Environmental Engineering of the University of Padua (Italy) and the other at the LTHE laboratory of the University of Grenoble (France). These tests allowed highlighting the dependence of bio-mechanical parameters on the initial state of the waste. The main result is that a slight aerobic pre-treatment is able in reducing the remaining time of biodegradation of the organic matter. As a consequence, both the amplitude and the time to fully ripening the landfill settlements also reduce
Geosynthetic interface friction using Force Procedure at the Tilting Plane.
No full textThe correct assessment of the interfacial properties between the geosynthetic surfaces in composite liner systems, as landfill covers, is an important issue to prevent the occurrence of potential slip surfaces.
Inclined Plane tests, using a Tilting Plane, are the most suitable tests for monitoring interface behaviour under low normal effective stress level.
According to recent studies, the test procedure, ruled by the European Standard EN ISO 12957-2, could overestimate the interface friction angle between the geosynthetic surfaces.
An original dual interpretation of this kind of test was recently proposed by the second and third authors: a complete understanding of a tilting test is based on the monitoring of the tangential displacement and/or of the force during the complete test. This new approach includes a light modification of the standard device. “Force Procedure” consists in measuring the force required to hold back the upper box. This contribution could allow a revision of the European Standard for Inclined Plane Test
Parametri di attrito all’interfaccia tra geosintetici in condizioni di carico statico e dinamico.
No full textDry friction behaviour of a geosynthetic interface using inclined plane and shaking table tests
No full textInclined plane test is widely used, especially in Europe, for the friction characterization of geosynthetics
liner systems, for example in landfill applications. However, interpretation of the test is more complex
and less consensual than for the direct shear test. In this paper, a comprehensive analysis of interface
behaviour at the Inclined Plane device is presented for a non-woven geotextile on a geomembrane in dry
condition.
New test procedure are proposed, and the related parameters of friction are defined in order to
properly characterise friction behaviour. For the Inclined Plane, the shear strength of a geosynthetic
interface cannot be characterised by a single parameter, as the interface behaviour is sensitive to the
different kinematic conditions.
To this purpose, a comparison is shown with the results of complementary tests carried out using the
Shaking Table test. For both test procedures, particular attention was paid to the influence of the relative
sliding velocity. Finally, the sensitivity of the interface to mechanical damage caused by large relative
displacements was quantified
- …
