Roadway Base and Subgrade Geocomposite Drainage Layers

2008 ◽  
pp. 35-35-17 ◽  
Author(s):  
BR Christopher ◽  
SA Hayden ◽  
A Zhao
Keyword(s):  
Drainage Layers

Clogging of landfill tyre and aggregate drainage layers by methanogenic leachate and implications for practice

2013 ◽  
Vol 33 (2) ◽  
pp. 431-444 ◽  
Author(s):  
R.P. Beaven ◽  
A.P. Hudson ◽  
K. Knox ◽  
W. Powrie ◽  
J.P. Robinson
Keyword(s):  
Drainage Layers

scholarly journals Study on drainage layer strategy for improving performance of glass fibrous coalescing filter

2020 ◽  
Author(s):  
chengwei xu ◽  
chenglong xiao ◽  
Yan yu ◽  
xiaodong si
Keyword(s):  
Pressure Drop ◽  
Pore Size ◽  
High Efficiency ◽  
Size Difference ◽  
Drainage Layer ◽  
Filtration Performance ◽  
Fibrous Filters ◽  
Drainage Layers ◽  
Commercial Glass ◽  
Positive Effect

The drainage layer strategy is a common method for improving filtration performance of coalescing filter. In this study, using the commercial glass fibrous filters, the influence of sub-high efficiency drainage layers on high efficiency coalescing filters were investigated experimentally. The efficiency of coalescing filter slight increases, whereas the total wet pressure drop reduces 0.32 kPa after assembling drainage layer. In addition, the influence of pore size, thickness and wettability on performance were evaluated. While the pore size of drainage layer decrease, the wet pressure drop reduces and quality factor increase. Likewise, the thickness of drainage layer also has positive effect on filtration performance. By contrast, the wettability has a weak affect on the filtration performance. As different coalescing filter with the same drainage layer, the improvement in the filtration performance increase with the decrease of pore size difference between the coalescing and drainage layers.

scholarly journals Seepage Analysis of a Multilayer Waste Slope considering the Spatial and Temporal Domains of Permeability

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Rong Yang ◽  
Zengguang Xu ◽  
Junrui Chai
Keyword(s):  
Distribution Curve ◽  
Numerical Models ◽  
Vertical Direction ◽  
Seepage Analysis ◽  
Drainage Layer ◽  
Finite Element Software ◽  
Pore Pressures ◽  
Two Factors ◽  
Drainage Layers ◽  
Waste Degradation

Landfilled municipal solid waste has evident heterogeneity, and clogging of the drainage layer can easily happen during operation of the landfill. These two factors significantly influence the distribution of leachate in a landfill. Herein, the distribution of waste permeability in the spatial and temporal domains was analyzed. Then, changes to the drainage-layer permeability in the temporal domain were fitted to these data. A simple model of multilayer waste slope was established combining the finite element software and a user subroutine. Herewith, changes of permeability in the waste and drainage layers were simulated, such that the heterogeneity of waste and the process of clogging of the drainage layer could be simulated. Then, the leachate distributions and transport conditions of nine schemes for landfill were analyzed. The results indicated that the distribution curve of waste-saturated permeability follows a logarithmic relation in the vertical direction, and the distribution curve of fresh-waste-saturated permeability follows a polynomial relation in time. After each landfill is worked for a few years, the drainage layer always encounters clogging problems of some kind and its permeability decreases by one to five orders of magnitude. Through numerical models, the simulation results of the permeability distribution in the spatial and temporal domains were found satisfactory. When the permeability distributions were layered in the buried depth, pore pressures and leachate levels are smaller than the logarithmic distributions. During the process of degradation, the pore pressures and leachate levels are increased slightly under the consideration of the polynomial distribution of waste permeability in time. With clogging of the permeability of the drainage layer, the pore pressures and leachate levels of landfill were found to be increasing gradually. To obtain results closer to that of actual situations, corresponding models should be established and analyzed based on a range of permeability, waste degradation rate, and degree of clogging.

Evaluation of Long-Term Performance of Pavement Drainage Layers on I-469 in Indiana

2008 ◽  
Vol 2045 (1) ◽  
pp. 77-84 ◽  
Author(s):  
Thomas D. White ◽  
A. Samy Noureldin ◽  
Dwayne Harris ◽  
John E. Haddock
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Subsurface Drainage ◽  
Pavement Performance ◽  
Triaxial Tests ◽  
Shear Stresses ◽  
Element Analysis ◽  
Drainage Layers ◽  
Falling Weight

Subsurface drainage is important for long-term pavement performance. Rational procedures to analyze and evaluate the design, reliability, and effectiveness of subsurface drainage systems are needed in order for their use to be recommended with confidence. Three pavement subdrainage test sections were constructed in 1995 on the eastbound driving lane of I-469 in Indiana, at the northern junction with I-69, between Stations 150+05 and 173+40. Presented are the original laboratory characterization and mechanistic evaluation for permanent deformation and stability of the test sections employing finite element analysis. Triaxial tests were conducted on all pavement layers of the sections. Falling weight deflectome-ter evaluations in 1995 and 1998 are also presented. Such measurements are not available after 1998 because compliance with Indiana Department of Transportation safety regulations is required at that location. Finite element analyses were conducted by using laboratory-measured material properties to predict pavement response to falling weight deflec-tometer loads, compare predicted and measured deflections, examine layer shear stability for shear stress and strength, and predict rutting. Long-term pavement performance indicators up until 2007 (including international roughness index and ground penetration radar), after 12 years of heavy truck traffic, are also presented. Finite element analysis predicted very well the deflections measured by the falling weight deflectometer and accumulated rutting of the three test sections. Comparisons of shear stresses and strengths indicated that the sections were stable. All long-term evaluations indicated that all drainage layers in the study sections have performed their function adequately and protected the subgrade.

scholarly journals Green Roof Design: State of the Art on Technology and Materials

2019 ◽  
Vol 11 (11) ◽  
pp. 3020 ◽  
Author(s):  
Stefano Cascone
Keyword(s):  
State Of The Art ◽  
Green Roof ◽  
Green Roofs ◽  
Future Research ◽  
Climate Conditions ◽  
Drainage Layers ◽  
Innovative Materials ◽  
Protection Filter ◽  
Roof Design ◽  
Selection Of

In order to consider green roofs as an environmentally friendly technology, the selection of efficient and sustainable components is extremely important. Previous review papers have mainly focused on the performance and advantages of green roofs. The objective of this paper is to examine the primary layers: The waterproof and anti-root membranes; the protection, filter, and drainage layers; the substrate; and the vegetation. First, the history, modern applications, benefits and classification are analyzed in order to present a well-defined state of the art of this technology. Then, the roles, requirements, characteristics, and materials are assessed for each green roof layers. This technology was compared to a conventional roof technology, Mediterranean climate conditions and their influence on green roof design were assessed, also comparing them with Tropical area and focusing on irrigation systems, examples about the commercial materials and products available in the market were provided and innovative materials coming from recycled sources were analyzed. Future research should evaluate new materials for green roof technologies, in order to enhance their performance and increase their sustainability. The information provided in this review paper will be useful to develop Mediterranean green roof guidelines for selecting suitable components and materials during the design and installation phases.

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